U.S. patent application number 13/630566 was filed with the patent office on 2014-04-03 for method for solution heat treated alloy components.
This patent application is currently assigned to UNITED TECHNOLOGIES CORPORATION. The applicant listed for this patent is David W. Anderson, Daniel A. Bales, Raymond C. Benn, David Ulrich Furrer, Eric A. Hansen, William F. Matzke, Ivan M. Schmidt, Chris Vargas. Invention is credited to David W. Anderson, Daniel A. Bales, Raymond C. Benn, David Ulrich Furrer, Eric A. Hansen, William F. Matzke, Ivan M. Schmidt, Chris Vargas.
Application Number | 20140090753 13/630566 |
Document ID | / |
Family ID | 50384099 |
Filed Date | 2014-04-03 |
United States Patent
Application |
20140090753 |
Kind Code |
A1 |
Vargas; Chris ; et
al. |
April 3, 2014 |
METHOD FOR SOLUTION HEAT TREATED ALLOY COMPONENTS
Abstract
A method for adjusting properties of components made of an alloy
includes providing historical data for one or more properties of
components made of an alloy and produced at different times. The
components are solution heat treated at a pre-established solution
heat treatment condition. A trending change in the one or more
properties is then identified and test specimens made of the alloy
are provided. The test specimens are divided into a plurality of
groups and solution heat treated at different conditions. The test
specimens are then mechanically tested to provide empirical data.
The empirical data is compared to performance criteria and a
solution heat treatment condition is identified over which the
empirical data meets the performance criteria. The pre-established
solution heat treatment condition is then adjusted for future ones
of the plurality of components according to the identified solution
heat treatment condition.
Inventors: |
Vargas; Chris; (West
Hartford, CT) ; Hansen; Eric A.; (Glastonbury,
CT) ; Benn; Raymond C.; (Madison, CT) ; Bales;
Daniel A.; (Avon, CT) ; Schmidt; Ivan M.;
(Niantic, CT) ; Anderson; David W.; (Cromwell,
CT) ; Furrer; David Ulrich; (East Hartford, CT)
; Matzke; William F.; (Battle Ground, WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Vargas; Chris
Hansen; Eric A.
Benn; Raymond C.
Bales; Daniel A.
Schmidt; Ivan M.
Anderson; David W.
Furrer; David Ulrich
Matzke; William F. |
West Hartford
Glastonbury
Madison
Avon
Niantic
Cromwell
East Hartford
Battle Ground |
CT
CT
CT
CT
CT
CT
CT
WA |
US
US
US
US
US
US
US
US |
|
|
Assignee: |
UNITED TECHNOLOGIES
CORPORATION
Hartford
CT
|
Family ID: |
50384099 |
Appl. No.: |
13/630566 |
Filed: |
September 28, 2012 |
Current U.S.
Class: |
148/508 |
Current CPC
Class: |
C21D 11/005 20130101;
C21D 11/00 20130101; C22F 1/10 20130101 |
Class at
Publication: |
148/508 |
International
Class: |
C21D 11/00 20060101
C21D011/00 |
Claims
1. A method for adjusting properties of components made of an
alloy, the method comprising: providing historical data for one or
more properties of a plurality of components made of an alloy and
that are produced at different times over a time period, wherein
the plurality of components are solution heat treated at a
pre-established solution heat treatment condition and precipitation
heat treated; identifying a trending change in the one or more
properties over the time period; providing test specimens made of
the alloy and that differ in shape from the plurality of
components; dividing the test specimens into a plurality of groups
and solution heat treating and precipitation heat treating each of
the plurality of groups at a different one of a plurality of heat
treatment conditions, each of the plurality of heat treatment
conditions including a set of at least a solution heat treatment
temperature, a heating rate and a cooling rate; mechanically
testing the test specimens after the solution heat treating and
precipitation heat treating to provide empirical data; comparing
the empirical data to predetermined performance criteria;
identifying a solution heat treatment condition from the plurality
of heat treatment conditions over which the empirical data meets
the predetermined performance criteria; and adjusting a
pre-established solution heat treatment condition for future ones
of the plurality of components according to the identified solution
heat treatment condition.
2. The method as recited in claim 1, wherein the alloy is a
nickel-based alloy.
3. The method as recited in claim 1, wherein the alloy is a
nickel-based alloy that has gamma double prime phase, gamma prime
phase and a delta phase present after the solution heat treating
and precipitation heat treatment.
4. The method as recited in claim 1, wherein the alloy is a
nickel-based alloy that has a gamma prime phase and a delta phase
present after the solution heat treating and precipitation heat
treatment.
5. The method as recited in claim 1, wherein the alloy is a
nickel-based alloy that has gamma prime phase present after the
solution heat treating and precipitation heat treatment.
6. The method as recited in claim 1, wherein the empirical data and
performance criteria include ultimate tensile strength, 0.2% yield
strength, tensile percent elongation and tensile reduction in
area.
7. The method as recited in claim 1, wherein the empirical data and
performance criteria include tensile stress rupture life, tensile
percent elongation and tensile reduction in area.
8. The method as recited in claim 1, further comprising solution
heat treating the future ones of the plurality of components at the
identified heat treatment condition to non-destructively qualify
that the future ones of the plurality of components meet the
predetermined performance criteria.
9. The method as recited in claim 1, including adjusting the
pre-established solution heat treatment condition for each of a
plurality of batches of the alloy, the plurality of batches of the
alloy varying from each other in chemical composition.
10. A method of estimating an unknown solvus for a phase of a given
alloy, the method comprising: providing empirical data of a
plurality of alloys from an alloy class, the empirical data at
least including chemical compositions, heating rates, cooling rates
and alloy solvus temperatures of the plurality of alloys; providing
an alloy chemical composition, a selected heating rate and a
selected cooling rate of another alloy from the alloy class that
has an unknown solvus temperature; estimating the unknown solvus
temperature based upon the empirical data to provide an estimated
solvus temperature of the alloy; and establishing a solution heat
treatment temperature corresponding to the estimated solvus
temperature at which to treat a component that includes the
alloy.
11. The method as recited in claim 10, wherein the estimating of
the unknown solvus temperature includes determining an influence of
the chemical compositions on the solvus temperatures of the
plurality of alloys.
12. The method as recited in claim 10, wherein the estimating of
the unknown solvus temperature includes determining an influence of
the heating rates on the solvus temperatures of the plurality of
alloys.
13. The method as recited in claim 10, wherein the estimating of
the unknown solvus temperature includes determining an influence of
the cooling rates on the solvus temperatures of the plurality of
alloys.
14. The method as recited in claim 10, wherein the estimating of
the unknown solvus temperature includes determining an influence of
each of the chemical compositions, the heating rates and the
cooling rates on the solvus temperatures of the plurality of
alloys.
15. The method as recited in claim 10, wherein: the estimating of
the unknown solvus temperature includes determining an influence of
the chemical compositions, heating rates and cooling rates on the
solvus temperatures of the plurality of alloys; and the estimating
of the unknown solvus temperature includes comparing the alloy
chemical composition, the selected heating rate and the selected
cooling rate of the alloy that has the unknown solvus temperature
to the chemical compositions, the heating rates and the cooling
rates of the plurality of alloys to provide the estimated solvus
temperature of the alloy.
16. The method as recited in claim 10, wherein the alloy class is a
nickel-based alloy.
17. The method as recited in claim 16, wherein the nickel-based
alloy has gamma double prime phase, gamma prime phase and a delta
phase present after a solution heat treatment and a precipitation
heat treatment.
18. The method as recited in claim 16, wherein the nickel-based
alloy has a gamma prime phase and a delta phase present after a
solution heat treatment and a precipitation heat treatment.
19. The method as recited in claim 16, wherein the nickel-based
alloy has gamma prime phase present after a solution heat treatment
and a precipitation heat treatment.
20. A method for selecting a solution heat treatment condition of
an alloy on a per-batch basis, the method comprising: for each
batch of an alloy, providing test specimens made of the alloy and
that differ in shape from the plurality of components; dividing the
test specimens into a plurality of groups and solution heat
treating and precipitation heat treating each of the plurality of
groups at a different one of a plurality of heat treatment
conditions, each of the plurality of heat treatment conditions
including a set of at least a solution heat treatment temperature,
a heating rate and a cooling rate; mechanically testing the test
specimens after the solution heat treating and precipitation heat
treating to provide empirical data; comparing the empirical data to
predetermined performance criteria; identifying a solution heat
treatment condition from the plurality of heat treatment conditions
over which the empirical data meets the predetermined performance
criteria; and adjusting a pre-established solution heat treatment
condition to treat a plurality of components according to the
identified heat treatment condition.
Description
BACKGROUND
[0001] This disclosure relates to alloy components that are
solution heat treated and, more particularly, relates to selecting
a solution heat treatment temperature for the components.
[0002] Alloy components may be solution heat treated at a
pre-selected temperature. The heat treatment is used to control the
microstructure of the alloy and obtain desired mechanical
properties within the components.
SUMMARY
[0003] A method for adjusting properties of components made of an
alloy according to an exemplary aspect of the present disclosure
includes providing historical data for one or more properties of a
plurality of components made of an alloy and that are produced at
different times over a time period, wherein the plurality of
components are solution heat treated at a pre-established solution
heat treatment condition. A trending change in the one or more
properties over the time period is then identified and test
specimens made of the alloy and that differ in shape from the
plurality of components are provided. The test specimens are
divided into a plurality of groups and each of the plurality of
groups is solution heat treated and precipitation heat treated at a
different one of a plurality of heat treatment conditions. Each of
the plurality of heat treatment conditions includes a set of at
least a solution heat treatment temperature, a heating rate and a
cooling rate. The test specimens are mechanically tested after the
solution heat treating and precipitation heat treating to provide
empirical data. The empirical data is compared to predetermined
performance criteria. A solution heat treatment condition is
identified from the plurality of heat treatment conditions over
which the empirical data meets the predetermined performance
criteria. A pre-established solution heat treatment condition is
adjusted for future ones of the plurality of components according
to the identified solution heat treatment condition.
[0004] In a further non-limiting embodiment, the alloy is a
nickel-based alloy.
[0005] In a further non-limiting embodiment of any of the foregoing
examples, the alloy is a nickel-based alloy that has gamma double
prime phase, gamma prime phase and a delta phase present after the
solution heat treating and precipitation heat treatment.
[0006] In a further non-limiting embodiment of any of the foregoing
examples, the alloy is a nickel-based alloy that has a gamma prime
phase and a delta phase present after the solution heat treating
and precipitation heat treatment.
[0007] In a further non-limiting embodiment of any of the foregoing
examples, the alloy is a nickel-based alloy that has gamma prime
phase present after the solution heat treating and precipitation
heat treatment.
[0008] In a further non-limiting embodiment of any of the foregoing
examples, the empirical data and performance criteria include
ultimate tensile strength, 0.2% yield strength, tensile percent
elongation and tensile reduction in area.
[0009] In a further non-limiting embodiment of any of the foregoing
examples, the empirical data and performance criteria include
tensile stress rupture life, tensile percent elongation and tensile
reduction in area.
[0010] A further non-limiting embodiment of any of the foregoing
examples includes solution heat treating the future ones of the
plurality of components at the identified heat treatment condition
to non-destructively qualify that the future ones of the plurality
of components meet the predetermined performance criteria.
[0011] A further non-limiting embodiment of any of the foregoing
examples includes adjusting the pre-established solution heat
treatment condition for each of a plurality of batches of the
alloy, the plurality of batches of the alloy varying from each
other in chemical composition.
[0012] A method of estimating an unknown solvus for a phase of a
given alloy according to an exemplary aspect of the present
disclosure includes providing empirical data of a plurality of
alloys from an alloy class, where the empirical data at least
includes chemical compositions, heating rates, cooling rates and
alloy solvus temperatures of the plurality of alloys. An alloy
chemical composition, a selected heating rate and a selected
cooling rate of another alloy from the alloy class that has an
unknown solvus temperature is provided. The unknown solvus
temperature is estimated based upon the empirical data to provide
an estimated solvus temperature of the alloy. A solution heat
treatment temperature is established corresponding to the estimated
solvus temperature at which to treat a component that includes the
alloy.
[0013] In a further non-limiting embodiment of any of the foregoing
examples, the estimating of the unknown solvus temperature includes
determining an influence of the chemical compositions on the solvus
temperatures of the plurality of alloys.
[0014] In a further non-limiting embodiment of any of the foregoing
examples, the estimating of the unknown solvus temperature includes
determining an influence of the heating rates on the solvus
temperatures of the plurality of alloys.
[0015] In a further non-limiting embodiment of any of the foregoing
examples, the estimating of the unknown solvus temperature includes
determining an influence of the cooling rates on the solvus
temperatures of the plurality of alloys.
[0016] In a further non-limiting embodiment of any of the foregoing
examples, the estimating of the unknown solvus temperature includes
determining an influence of each of the chemical compositions, the
heating rates and the cooling rates on the solvus temperatures of
the plurality of alloys.
[0017] In a further non-limiting embodiment of any of the foregoing
examples, the estimating of the unknown solvus temperature includes
determining an influence of the chemical compositions, heating
rates and cooling rates on the solvus temperatures of the plurality
of alloys and the estimating of the unknown solvus temperature
includes comparing the alloy chemical composition, the selected
heating rate and the selected cooling rate of the alloy that has
the unknown solvus temperature to the chemical compositions, the
heating rates and the cooling rates of the plurality of alloys to
provide the estimated solvus temperature of the alloy.
[0018] In a further non-limiting embodiment of any of the foregoing
examples, the alloy class is a nickel-based alloy.
[0019] In a further non-limiting embodiment of any of the foregoing
examples, the nickel-based alloy has gamma double prime phase,
gamma prime phase and a delta phase present after a solution heat
treatment and a precipitation heat treatment.
[0020] In a further non-limiting embodiment of any of the foregoing
examples, the nickel-based alloy has a gamma prime phase and a
delta phase present after a solution heat treatment and a
precipitation heat treatment.
[0021] In a further non-limiting embodiment of any of the foregoing
examples, the nickel-based alloy has gamma prime phase present
after a solution heat treatment and a precipitation heat
treatment.
[0022] A method for selecting a solution heat treatment condition
of an alloy on a per-batch basis according to an exemplary aspect
of the present disclosure includes, for each batch of an alloy,
providing test specimens made of the alloy and that differ in shape
from the plurality of components. The test specimens are divided
into a plurality of groups and each of the plurality of groups is
solution heat treated at a different one of a plurality of heat
treatment conditions and precipitation heat treated. Each of the
plurality of heat treatment conditions includes a set of at least a
solution heat treatment temperature, a heating rate and a cooling
rate. The test specimens are mechanically tested after the solution
heat treating and precipitation heat treating to provide empirical
data. The empirical data is compared to predetermined performance
criteria to identify a solution heat treatment condition from the
plurality of heat treatment conditions over which the empirical
data meets the predetermined performance criteria. A
pre-established solution heat treatment condition is established to
treat a plurality of components according to the identified heat
treatment condition.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The various features and advantages of the present
disclosure will become apparent to those skilled in the art from
the following detailed description. The drawings that accompany the
detailed description can be briefly described as follows.
[0024] FIG. 1 shows an example method for adjusting properties of
components made of an alloy.
[0025] FIG. 2 shows an example Time-Temperature-Transformation
diagram of a legacy alloy and a more recently-produced alloy.
[0026] FIG. 3 shows a table of empirical data trend for solution
heat treating temperature, cooling rate and heating rate.
[0027] FIG. 4 shows a heat treatment temperature capability curve
that can be used as part of the method for adjusting properties of
the components.
[0028] FIG. 5 shows a method of estimating an unknown solvus for a
given alloy.
DETAILED DESCRIPTION
[0029] FIG. 1 schematically shows a method 20 for adjusting
properties of components made of an alloy. For example, the
components can be diffuser cases or structural components for gas
turbine engines, but are not necessarily limited to such
components. As will be described in more detail, the response of a
nominal chemistry alloy to a pre-established solution heat
treatment condition (i.e. a baseline condition) may vary over time
such that one or more properties of the alloy change over that
time. While random changes in the properties taken from
time-to-time may be expected, a trending change is undesired and
thus the pre-established solution heat treatment condition can be
adjusted according to the method 20 to ensure that performance
criteria are met.
[0030] As shown in FIG. 1, the method 20 includes, at step 22,
providing historical data for one or more properties of a plurality
of components that are made of an alloy and that are produced at
different times over a time period. For example, the time period
may be over a course of weeks, a year or multiple years. The
components are solution heat treated at a pre-established solution
heat treatment condition. That is, the pre-established solution
heat treatment condition is constant over the time period. In
theory, the historical data should not change much over the time
period. However, due to slight variations in the chemical
composition of the alloy that can occur over the time period, the
historical data can change such that one or more properties
approach pre-determined performance criteria. In this regard, step
24 includes identifying a trending change in the one or more
properties over the time period. For example, the properties can
include ultimate tensile strength, 0.2% yield strength, tensile
percent elongation and tensile reduction an area. In a further
example, the properties can include, or can also include, stress
rupture life, percent elongation and percent reduction in area, at
given test conditions, such as 1200.degree. F./649.degree. C. and
90 kilo-pounds per square inch/620.5 megapascals; 1500.degree.
F./815.6.degree. C. and 45 kilo-pounds per square inch/310
megapascals; or 1300.degree. F./704.degree. C. and 65 kilo-pounds
per square inch/448 megapascals. The test conditions may vary
depending upon the alloy class. Fatigue or other properties can
also be used.
[0031] Once the trending change in one or more of the properties is
identified, a series of steps as follows can be used to adjust the
pre-established solution heat treatment condition and thereby
improve the one or more properties that have trended in an
undesired direction over the time period. Step 26 includes
providing test specimens made of the alloy and that differ in shape
from the plurality of locations and components. That is, the
components have a shape that is designed for the intended end use,
while the test specimens have a standardized shape that is
appropriate for mechanical testing, such as a "dog-bone" or
"dumb-bell" shape. The test specimens are untreated, at least with
regard to the solution heat treatment.
[0032] The test specimens are then divided at step 28 into a
plurality of groups. The groups are solution heat treated and
precipitation heat treated at a different one of a plurality of
heat treatment conditions. Each of the plurality of heat treatment
conditions includes a set of at least a solution heat treatment
temperature, a heating rate and a cooling rate. After the solution
heat treatment and precipitation heat treatment, the test specimens
are mechanically tested at step 30 to provide empirical data. As
discussed above, the one or more properties can include certain
mechanical properties of the plurality of components. In this
regard, the empirical data that is collected in step 30 by
mechanically testing the test specimens and the performance
criteria include the same properties. The empirical data is then
compared at step 32 to pre-determined performance criteria. For
example, the pre-determined performance criteria can correspond to
minimum or desired mechanical properties of the components for
proper operation of the components in the intended end use.
[0033] Step 34 then includes identifying a solution heat treatment
condition from the plurality of heat treatment conditions over
which the empirical data meets the predetermined performance
criteria. Once the solution heat treatment condition is identified,
step 36 then includes adjusting the pre-established solution heat
treatment condition for future ones of the plurality of components
according to the identified solution heat treatment condition. The
adjustment to the pre-established solution heat treatment condition
can include changing the solution heat treatment temperature, the
heating rate, the cooling rate or any combination thereof. The
testing and verification of the properties of the test specimens
and then adjusting the pre-established solution heat treatment
condition ensures that the one or more properties of the components
meet the pre-determined performance criteria.
[0034] Although the method 20 can be applied to many different
types or classes of alloys, an alloy of interest for diffuser cases
and other gas turbine engine components is nickel-based alloy, one
example of which can be found in U.S. Pat. No. 4,888,253,
incorporated herein by reference, which has gamma double prime
phase, gamma prime phase and delta phase. In another example, the
alloy is a nickel-based alloy that has gamma prime phase and delta
phase, examples of which can include alloys found in U.S. Pat. No.
6,730,264, incorporated herein by reference, and Alloy 718Plus). In
another example, the alloy is a nickel-based alloy that has gamma
prime phase, one example of which includes Waspaloy.
[0035] Additionally, the method 20 can be used to non-destructively
qualify that the components meet the pre-determined performance
criteria. For example, by mechanically testing the test specimens
and comparing the empirical data to the pre-determined performance
criteria, a user can conclude that the plurality of components that
are solution heat treated at the adjusted pre-established solution
heat treatment condition also meet the pre-determined performance
criteria.
[0036] The following example is based upon a nickel-based alloy
that has a gamma double prime phase, a gamma prime phase and a
delta phase after solution heat treating and precipitation heat
treatment. Historical data were collected for one or more
properties of components made of the alloy over a period of years.
A trending change in one or more of the properties was identified
over the time period and it was determined, as represented in FIG.
2, that the response of the alloy to the pre-established solution
heat treatment condition had changed over the time period. FIG. 2
shows a Time-Temperature-Transformation diagram for the
precipitation of the delta phase, gamma double prime phase and the
gamma prime phase for a legacy alloy from several years prior to
the study versus the same for a more recent batch of the alloy. As
shown in the diagram, the lines L.sub.1 and L.sub.2 represent,
respectively, the Time-Temperature-Transformation curves for delta
phase precipitation start (interdendritic grain boundaries) and
finish (dendritic grain core), for the legacy alloy. The lines
L.sub.3 and L.sub.4 represent, respectively,
Time-Temperature-Transformation curves for the delta phase
precipitation start (interdendritic grain boundaries) and finish
(dendritic grain core) for the more recent alloy. The T-T-T curve
for the start of gamma prime and gamma double prime phase
precipitation is shown in relation to the delta phase curves. The
curves L.sub.3 and L.sub.4 for the more recent alloy differ from
the curves L.sub.1 and L.sub.2 of the legacy alloy and thus
indicate that the response of the more recent alloy to solution
heat treatment has changed over time in comparison to the legacy
alloy. The change was further evidenced in microstructural
analysis, which showed a greater amount of delta phase
precipitation in the more recent alloy than in the legacy alloy.
The increased amount of the delta phase consumes more niobium in
the microstructure, which debits the precipitation of the gamma
double prime and gamma prime phases and thus changes the alloy
properties.
[0037] As shown in FIG. 3, test specimens of the more recent alloy
were mechanically tested as described herein and the influence of
the solution heat treatment temperature, cooling rate and heating
rate on the properties were determined. In the table shown in FIG.
3, a "zero" indicates insignificant or no influence of a condition
on the given property, an "up arrow" indicates that the property
increased as the given condition increased, and a "down arrow"
indicates that the property decreased as the given condition
decreased.
[0038] As shown in FIG. 4, each property was plotted on a graph
versus the solution heat treatment condition, here shown as the
solution heat treatment temperature. The property, as represented
by line T, was then compared to a performance requirement,
represented at line R. Thus, the graph is essentially a solution
heat treatment temperature capability curve that facilitates
identifying a condition range over which the empirical data meets
the pre-determined performance criteria, rather than a single point
condition that meets the performance criteria. As shown in the
graph in FIG. 4, a temperature range TR was then be identified over
which the empirical data meets the predetermined performance
criteria. For example, the identified temperature range began at a
temperature that is beyond the intersection of the trend line T and
the performance requirement line R, to provide a margin above the
performance requirement. In the example, a pre-established solution
heat treatment condition of 1825-1875.degree. F.
(996.1-1024.degree. C.) and a cooling rate of 75.degree. F.
(24.degree. C.) per minute was adjusted to 1860-1900.degree. F.
(1016-1038.degree. C.) and a cooling rate of 25.degree. F.
(3.9.degree. C.) per minute.
[0039] Similarly, the heating rate and/or the cooling rate (or
ranges thereof) can be identified. Once the condition was
identified, components that were made of the same alloy as the test
specimens that were used to identify the condition range, were
solution heat treated at the identified condition to ensure that
the components met the property requirements or performance
criteria.
[0040] As another example, a variation of the method 20, optionally
without steps 22 and 24, can be used to adjust the pre-established
solution heat treatment condition on a per-batch basis of the
alloy. As used herein, a "batch" differentiates the alloy by time
of production of the alloy, but does not necessarily mean that the
alloy was produced using batch processing techniques. For example,
each batch of the alloy may vary slightly from a nominal chemical
composition. Typically, chemical compositions of alloys, such as
nickel-based alloys, are defined with regard to specific ranges of
each element of the chemical composition. Thus, the actual amount
of any given element can vary within the specified range of that
element from batch-to-batch of the alloy. These slight differences
in chemical compositions between batches can change the response of
a batch to a given baseline or pre-established solution heat
treatment condition. In this regard, the modified method 20 can be
used on each batch to adjust or tailor the pre-established solution
heat treatment condition for that particular batch. That is, one
batch of the alloy can have a first adjusted pre-established
solution heat treatment condition and another, different batch of
the alloy can have a different adjusted pre-established solution
heat treatment condition that differs in at least one of solution
heat treatment temperature, heating rate or cooling rate. This
allows the properties of the batch of the alloy, and thus the
properties of the components that are to be produced from that
batch of the alloy, to be tailored to the particular batch of the
alloy.
[0041] FIG. 5 shows an example method 50 of estimating an unknown
solvus for a phase of a given alloy. As used herein, the term
"solvus" or variations thereof refer to a line, boundary or point
that represents a separation between a homogenous solid solution
and a multi-phase microstructure, as a function of temperature. In
the solution heat treating of alloy components, the solvus can be
used to select the solution heat treatment temperature at which the
components are to be treated to obtain a desired microstructure and
thus desired properties. However, the solvus can vary depending
upon a number of factors and thus the response of a given alloy to
a pre-established solution heat treatment condition can vary.
Moreover, although an unknown solvus for a given alloy can be
experimentally determined, such a determination can be somewhat
complex, especially when trying to select from various different
alloys and determine appropriate solution heat treatment conditions
for those alloys. Thus, as will be described, the method 50
provides a technique for estimating an unknown solvus for a given
alloy based upon empirical data of other alloys.
[0042] The method 50 includes, at step 52, providing empirical data
of a plurality of alloys from an alloy class. For the purpose of
this disclosure, an alloy class is determined according to the base
metal (most abundant metal) of the alloy. For example, nickel-based
alloys are considered to be an alloy class. Thus, the alloys from
which the empirical data is provided all include the same base
metal but may differ in the amounts and/or types of other elements.
In a further example, the alloys from which the empirical data is
provided can have all of the same elements, with multiple elements
being present in different amounts in the alloys.
[0043] The empirical data at least includes chemical compositions,
heating rates, cooling rates and alloy solvus temperatures of the
plurality of alloys. At step 54, an alloy chemical composition, a
selected heating rate and a selected cooling rate of another alloy
from the alloy class that has an unknown solvus temperature are
provided. At step 56, the unknown solvus temperature is then
estimated based upon the empirical data to provide an estimated
solvus temperature of the alloy. A solution heat treatment
temperature corresponding to the estimated solvus temperature is
then established at which to heat treat a component that includes
the alloy.
[0044] For example, estimation of the unknown solvus temperature
can include determining an influence of one or more of the chemical
compositions, the heating rates and the cooling rates on the solvus
temperatures of the plurality of the alloys. For example, by
comparing the chemical compositions, the influence of chemical
composition with regard to one or more of the elements on a
baseline solvus temperature can be determined. Similarly, the
influence of the heating rates and the cooling rates on a baseline
solvus temperature can be determined. By then comparing the
chemical composition, the selected heating rate and the selected
cooling rate of the alloy of unknown solvus temperature to the
empirical data and determined influences, the unknown solvus
temperature of the alloy can be estimated. Optionally, the method
50 can further include a verification of the selected solution heat
treatment temperature. The verification can include experimental
testing of the alloy, components formed of the alloy or a
combination thereof. The selected solution heat treatment
temperature can then be modified based upon the verification
results.
[0045] A component that is made of the same alloy as the alloy with
the unknown solvus temperature can then be solution heat treated
according to the estimated solvus temperature, selected heating
rate and selected cooling rate, without actual testing or
determination of the unknown solvus temperature. For example, the
selected solution heat treating temperature of the alloy can be a
pre-determined increment above the estimated solvus
temperature.
[0046] In another application of the present disclosure, variations
in composition from elemental changes, such as niobium content, can
be characterized by their effect on the empirical data, which may
be reflected in the respective heat treatment temperature
capability curve. The empirical property versus temperature may
indicate changes in the resultant best-fit curve in FIG. 2, e.g.,
higher or lower shifts from the nominal composition curve.
Comparison of such compositional effects provides quantitative
correlation curves that can be used to estimate the respective
changes in the solution temperature. Hence, a given heat chemistry
determination at the melt stage can be compared with the database
of compiled heat treatment capability curves to determine the
appropriate solution heat treatment conditions that meet the
performance criteria.
[0047] Although a combination of features is shown in the
illustrated examples, not all of them need to be combined to
realize the benefits of various embodiments of this disclosure. In
other words, a system designed according to an embodiment of this
disclosure will not necessarily include all of the features shown
in any one of the Figures or all of the portions schematically
shown in the Figures. Moreover, selected features of one example
embodiment may be combined with selected features of other example
embodiments.
[0048] The preceding description is exemplary rather than limiting
in nature. Variations and modifications to the disclosed examples
may become apparent to those skilled in the art that do not
necessarily depart from the essence of this disclosure. The scope
of legal protection given to this disclosure can only be determined
by studying the following claims.
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