U.S. patent application number 15/514826 was filed with the patent office on 2017-08-03 for method for removing prior particle boundary and hole defect of powder metallurgy high-temperature alloy.
This patent application is currently assigned to CENTRAL SOUTH UNIVERSITY. The applicant listed for this patent is CENTRAL SOUTH UNIVERSITY. Invention is credited to Qinglong DUAN, Yang GUO, Boyun HUANG, Zuming LIU, Mengmei MA, Pengfei SU.
Application Number | 20170216919 15/514826 |
Document ID | / |
Family ID | 56880215 |
Filed Date | 2017-08-03 |
United States Patent
Application |
20170216919 |
Kind Code |
A1 |
LIU; Zuming ; et
al. |
August 3, 2017 |
METHOD FOR REMOVING PRIOR PARTICLE BOUNDARY AND HOLE DEFECT OF
POWDER METALLURGY HIGH-TEMPERATURE ALLOY
Abstract
A method for removing prior particle boundaries and hole defects
of a powder metallurgy high-temperature alloy. The method includes
performing mechanical ball milling treatment on an atomized powder,
thermosetting the powder to form a shape, and preparing a powder
metallurgy high-temperature alloy.
Inventors: |
LIU; Zuming; (Hunan, CN)
; SU; Pengfei; (Hunan, CN) ; HUANG; Boyun;
(Hunan, CN) ; DUAN; Qinglong; (Hunan, CN) ;
GUO; Yang; (Hunan, CN) ; MA; Mengmei; (Hunan,
CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CENTRAL SOUTH UNIVERSITY |
Hunan |
|
CN |
|
|
Assignee: |
CENTRAL SOUTH UNIVERSITY
Hunan
CN
|
Family ID: |
56880215 |
Appl. No.: |
15/514826 |
Filed: |
March 8, 2016 |
PCT Filed: |
March 8, 2016 |
PCT NO: |
PCT/CN2016/075845 |
371 Date: |
March 28, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B22F 9/04 20130101; C22C
1/0433 20130101; B22F 2998/10 20130101; C22C 1/04 20130101; B22F
3/12 20130101; B22F 2998/10 20130101; B22F 2009/043 20130101; B22F
3/15 20130101; B22F 2998/10 20130101; B22F 2009/043 20130101; B22F
3/20 20130101; B22F 2998/10 20130101; B22F 2009/043 20130101; B22F
3/105 20130101 |
International
Class: |
B22F 3/12 20060101
B22F003/12; C22C 1/04 20060101 C22C001/04 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 9, 2015 |
CN |
201510103503.6 |
Claims
1. A method for removing prior particle boundaries and hole defects
of a powder metallurgy high-temperature alloy, comprising: first
performing mechanical ball milling treatment on high-temperature
alloy powder prepared by using an atomization method to prepare
surface activated solid powder, then thermosetting the powder to
form a shape, and preparing a powder metallurgy high-temperature
alloy.
2. The method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy according to
claim 1, wherein granularity of the atomized alloy powder is less
than or equal to 150 .mu.m.
3. The method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy according to
claim 1, wherein in ball milling, a used ball mill is one of a
planetary ball mill, a stirring ball mill, and a roller drum ball
mill.
4. The method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy according to
claim 3, wherein ball milling is performed under protection of an
inert gas.
5. The method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy according to
claim 3, wherein atomized powder is put into a ball mill pot with a
ball-to-powder ratio of: (8-12): 1, and ball milling is performed
in a planetary ball mill for 1-4 h at a ball milling rotation speed
of 250-350 r/min.
6. The method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy according to
claim 3, wherein atomized powder is put into a ball mill pot with a
ball-to-powder ratio of: (8-15): 1, and ball milling is performed
in a stirring ball mill for 2-6 h at a ball milling rotation speed
of 60-150 r/min.
7. The method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy according to
claim 4, wherein thermosetting forming uses one forming manner of
hot iso-hydrostatic forming, hot extrusion forming, and plasma
sintering forming.
8. The method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy according to
claim 7, wherein a processing parameter of the hot iso-hydrostatic
forming is 1000-1250.degree. C./100-150 MPa/4 h; processing
parameters of the hot extrusion forming are: performing hot
extrusion forming at 900-1200.degree. C.; an extrusion ratio of the
hot extrusion forming is (6-15): 1; and a processing parameter of
the plasma sintering forming is: 1000-1250.degree. C./40-150
MPa/5-10 min.
9. The method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy according to
claim 8, wherein solution treatment and aging treatment are
performed on a material of the high-temperature alloy formed by
thermosetting.
10. The method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy according to
claim 9, wherein processing parameters of the solution treatment
are: performing heat preservation for 1-2 h at 1000-1250.degree.
C., and performing air cooling; and processing parameters of the
aging treatment are: performing heat preservation for 4-10 h at
700-900.degree. C., and performing air cooling.
11. The method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy according to
claim 1, wherein thermosetting forming uses one forming manner of
hot iso-hydrostatic forming, hot extrusion forming, and plasma
sintering forming.
12. The method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy according to
claim 2, wherein thermosetting forming uses one forming manner of
hot iso-hydrostatic forming, hot extrusion forming, and plasma
sintering forming.
13. The method for removing prior particle boundaries and hole
detects of a powder metallurgy high-temperature alloy according to
claim 3, wherein thermosetting forming uses one forming mariner of
hot iso-hydrostatic forming, hot extrusion forming, and plasma
sintering forming.
14. The method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy according to
claim 5, wherein thermosetting forming uses one forming manner of
hot iso-hydrostatic forming, hot extrusion forming, and plasma
sintering forming.
15. The method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy according to
claim 6, wherein thermosetting forming uses one forming manner of
hot iso-hydrostatic forming, hot extrusion forming, and plasma
sintering forming.
Description
BACKGROUND
[0001] 1. Field of the Disclosure
[0002] The disclosure relates to a method for removing prior
particle boundaries and hole defects of a powder metallurgy
high-temperature alloy, and belongs to the powder metallurgy
material field.
[0003] 2. Description of Related Art
[0004] Defects, such as prior particle boundaries (PPB), internal
holes, or thermal induction holes of a powder metallurgy
high-temperature alloy are main defects of a powder
high-temperature alloy, and are difficult to be removed once
formed, and severely reduce mechanical properties of an alloy.
[0005] With respect to the defect of prior particle boundaries of
the powder metallurgy high-temperature alloy, Chinese patent
CN102409276A discloses a method for removing prior particle
boundaries of a powder metallurgy high-temperature alloy,
comprising: performing high-temperature solution treatment on a
powder metallurgy high-temperature alloy after direct hot isostatic
pressing at a high-temperature solution treatment temperature of
1180-1220.degree. C., and performing heat preservation for 1.5-4 h,
so as to effectively remove or weaken prior particle boundaries.
Chinese patent CN102676881A discloses a nickel-based powder
metallurgy high-temperature alloy capable of removing prior
particle boundaries. The alloy comprises FGH4096 and FGH4097; Hf
with a percentage by weight of 0.15-0.9% is additionally added
during a smelting process of the two alloys. MC type carbides are
formed in powder particles by adding the element, namely the Hf, to
reduce precipitation on the prior particle boundaries, so that the
prior particle boundaries in the nickel-based powder metallurgy
high-temperature alloy is removed after standard heat treatment is
performed on the nickel-based powder metallurgy high-temperature
alloy after direct hot isostatic pressing, and notch sensitivity of
the alloy is improved in the aspect of mechanical properties.
Chinese patent CN103551573A discloses a high-temperature alloy
powder hot isostatic pressing process capable of preventing phase
precipitation of prior particle boundaries. A hot isostatic
pressing temperature in a first step should be within the range
between an incipient melting temperature of a low-melting-point
phase in the powder particles and a solidus of completely
homogenized alloy plus 15.degree. C.; gas pressure should be
greater than or equal to 90 MPa; and time is greater than or equal
to 20 min and less than or equal to 1 h. Heating is stopped after
the first step is finished; a powder capsule is cooled in a furnace
to a temperature below the incipient melting temperature of the
low-melting-point phase of the alloy powder to preserve heat; the
heat preservation process is a second step; holding time in the
second step is greater than or equal to 2 h, to ensure that the
low-melting-point phase formed during cooling after the first step
can be completely dissolved during the heat preservation process
and the pressure is greater than or equal to 90 MPa; heating is
stopped and the capsule is cooled in the furnace to room
temperature after the second step is finished. The disclosure can
prevent precipitation of precipitated phases of carbides, and the
like along prior particle boundaries of powder, so as to obtain a
compact alloy with microscopic structures as equiaxed crystals.
Chinese patent CN103447341A discloses an equal-channel extrusion
mold for forming a powder high-temperature alloy blank, and the
mold is used for improving organizational characteristics of a
powder high-temperature alloy blank. After a blank enters the mold,
a round section of the blank is twisted to be elliptical and then
to be round again, and the deformation is a combination of twisting
and shearing deformation and extruding deformation, and thus a
combination of multiple deformation modes in one-pass extruding
process is implemented. At a transitional section of deformation
and twisting, due to twisting deformation of an elliptical twisting
surface, the blank rotates and is subjected to shearing strain
under an action of shearing stress, so as to implement shearing and
crushing of crystal grains and further achieve the effect of
refining the grains. Simultaneously, since the blank is limited by
a mold cavity, intracrystalline deformation of the blank in the
state of pressure stress is difficult, and thus the development of
various original microscopic defects in a deformed body can be
inhibited. Since the refining effect of the grains in the
disclosure is obvious, prior particle boundaries are removed
thoroughly, and comprehensive mechanical properties of the powder
high-temperature alloy blank are obviously improved.
[0006] The foregoing disclosures all remove prior boundaries of
powder particles by treating green bodies after powder forming,
which is a remedial measure adopted after the prior boundaries of
powder particles are formed. Limited by processing factors, the
effect of removing the prior boundaries of powder particles is
limited, or industrial application cannot be implemented.
[0007] The foregoing patents for invention do not relate to how to
remove hole effects of a powder metallurgy high-temperature
alloy.
[0008] The hole defects in a powder high-temperature alloy comprise
internal holes and thermal induction holes. The internal holes are
mainly residual holes caused by powder hollow defects; and the
thermal induction holes are hole defects caused by expansion
generated by residual gases in a heat treatment process. Therefore,
the powder hollow defects are main sources of the hole defects of
the powder high-temperature alloy.
[0009] A hollow center of powder is a defect that commonly exists
in atomized powder, and is determined by atomization process
characteristics, and cannot be avoided. A hollow center formed
inside atomized powder is completely sealed, and is difficult to be
removed in a subsequent powder forming process, and resides inside
a material to form a residual hole. Residual gases sealed in
atomization hollow defects expand in a subsequent heat treatment
process to form thermal induction holes, or induce cracks. The
holes severely reduce mechanical properties of a powder
high-temperature alloy, in particular, creep rupture life and
fatigue properties.
[0010] Currently, in powder prepared by using an atomization
process, a hollow ratio of large-particle-size powder is relatively
high. For a long time, hollow powder is removed by means of powder
screening in the art. A screening method can remove
large-particle-size hollow powder, but cannot completely remove
hollow powder, because hollow defects also occur to screened
small-size powder. A control atomization process is generally used
to control hollow defects that occur to atomized powder. However,
characteristics of an atomization process determine that the
control atomization process can only reduce a powder hollow ratio,
but cannot completely remove powder hollow defects.
[0011] With respect to internal holes and thermal induction holes,
caused by powder hollow defects, of a powder high-temperature alloy
material, there has not been any public report home and abroad that
internal holes and thermal induction holes are removed by removing
hollow defects of atomized alloy powder.
[0012] So far, there has not been any public report home and abroad
that hollow defects of atomized alloy powder are removed by means
of ball milling treatment, to obtain surface activated solid
powder, thereby removing prior boundaries, internal holes, and
thermal induction holes of powder particles.
SUMMARY
[0013] The disclosure is directed to provide a method for removing
prior particle boundaries and hole defects of a powder metallurgy
high-temperature alloy.
[0014] A method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy of the
disclosure includes first performing mechanical ball milling
treatment on high-temperature alloy powder prepared by using an
atomization method to prepare surface activated solid powder, then
thermosetting the powder to form a shape, and preparing a powder
metallurgy high-temperature alloy.
[0015] In a method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy of the
disclosure, granularity of the atomized alloy powder is less than
or equal to 150 .mu.m (-100 meshes), preferably less than or equal
to 106 .mu.m (-150 meshes), and further preferably less than or
equal to 75 .mu.m (-200 meshes).
[0016] In a method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy of the
disclosure, in ball milling, a used ball mill is one of a planetary
ball mill, a stirring ball mill, and a roller drum ball mill, and
preferably the planetary ball mill.
[0017] In a method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy of the
disclosure, ball milling is performed under protection of an inert
gas.
[0018] In a method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy of the
disclosure, atomized powder is put into a ball mill pot with a
ball-to-powder ratio of: (8-12): 1, and ball milling is performed
in a planetary ball mill for 1-4 h at a ball milling rotation speed
of 250-350 r/min.
[0019] In a method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy of the
disclosure, atomized powder is put into a ball mill pot with a
ball-to-powder ratio of (8-15): 1, and ball milling is performed in
a stirring ball mill for 2-6 h at a ball milling rotation speed of
60-150 r/min.
[0020] In a method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy of the
disclosure, thermosetting forming uses one forming manner of hot
iso-hydrostatic forming, hot extrusion forming, and plasma
sintering forming.
[0021] In a method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy of the
disclosure, the hot iso-hydrostatic forming is: 1000-1250.degree.
C./100-150 MPa/4 h hot iso-hydrostatic forming.
[0022] In a method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy of the
disclosure, the hot extrusion forming is: putting mixed powder
obtained in step I into a steel capsule, vacuuming the steel
capsule to equal to or less than 10.sup.-1 Pa, performing
degasification for equal to or greater than 60 min, and performing
sealing welding; and then performing hot extrusion forming at
900-1200.degree. C. with an extrusion ratio of (6-15): 1.
[0023] In a method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy of the
disclosure, the plasma sintering forming is: 1000-1250.degree.
C./40-150 MPa/5-10 min plasma sintering forming.
[0024] In a method for removing prior particle boundaries and hole
defects of a powder metallurgy high-temperature alloy of the
disclosure, solution treatment and aging treatment are performed on
a material of the high-temperature alloy formed by thermosetting;
processing parameters of the solution treatment are: performing
heat preservation for 1-2 h at 1000-1250.degree. C., and performing
air cooling; and processing parameters of the aging treatment are:
performing heat preservation for 4-10 h at 700-900.degree. C., and
performing air cooling.
ADVANTAGES AND POSITIVE EFFECTS OF THE DISCLOSURE
[0025] The present invention proposes to perform mechanical ball
milling treatment on atomized powder to improve surface activity of
the powder and remove internal hollow defects of powder particles,
so as to remove prior boundaries, internal holes, and thermal
induction holes of the powder particles, thereby improving
comprehensive mechanical properties.
[0026] After ball milling treatment is performed on atomized
powder, surfaces of the powder are activated, and powder with high
surface activity is obtained, so that in thermosetting forming,
prior boundaries of the powder can be effective removed to improve
interface bonding strength. Powder deforms after ball milling, and
internal hollow defects and condensation shrinkage cavities of
powder particles are removed to obtain completely solid powder. A
gas sealed in the solid powder is released, so as to effectively
remove internal holes and thermal induction holes in thermosetting
forming, thereby improving comprehensive mechanical properties. The
atomized powder deforms after ball milling treatment, so as to
facilitate recrystallization to form equiaxed crystal structures,
thereby improving properties.
[0027] Based on the above, according to a method for removing prior
particle boundaries and hole defects of a powder metallurgy
high-temperature alloy, ball milling treatment is performed on
atomized pre-alloyed powder to obtain solid powder with high
surface activity, then thermosetting forming is performed to
prepare a powder metallurgy high-temperature alloy. The disclosure
has a simple process and high production efficiency, so as to
facilitate large-scale preparation and application.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The accompanying drawings are included to provide a further
understanding of the disclosure, and are incorporated in and
constitute a part of this specification. The drawings illustrate
embodiments of the disclosure and, together with the description,
serve to explain the principles of the disclosure.
[0029] FIG. 1 is a metallographic microscopic structure of Rene 104
nickel-based high-temperature alloy prepared by performing plasma
sintering forming on atomized nickel-based high-temperature alloy
powder of a comparative example of the disclosure.
[0030] FIG. 2 is a scanning electronic microscope (SEM) diagram of
a cross section of nickel-based high-temperature alloy atomized
powder in embodiment 1 of the disclosure.
[0031] FIG. 3 is an SEM diagram of a cross section of powder after
mechanical ball milling is performed on nickel-based
high-temperature alloy atomized powder in embodiment 1 of the
disclosure.
[0032] FIG. 4 is a metallographic microscopic structure of Rene 104
nickel-based high-temperature alloy prepared by performing plasma
sintering forming after mechanical ball milling is performed on
atomized nickel-based high-temperature alloy powder in embodiment 1
of the disclosure.
[0033] According to a metallographic observation result of FIG. 1,
obvious prior particle boundaries (PPB) occur to microscopic
structures of the nickel-based high-temperature alloy prepared by
directly forming atomized powder, and 1 and 2 in FIG. 1 both
indicate prior particle boundaries.
[0034] According to an SEM observation result of FIG. 2, obvious
hollow defects occur to some atomized powder in embodiment 1, and
parts 3, 4, 5, and 6 in FIG. 2 are all hollow defects.
[0035] According to an SEM observation result of FIG. 3, after
mechanical ball milling is performed on atomized powder in
embodiment 1, no hollow phenomenon is observed on a cross section
of powder.
[0036] According to an observation result of an optical microscope
of FIG. 4, no obvious prior particle boundaries are observed on
microscopic structures of the nickel-based high-temperature alloy
prepared in embodiment 1.
DESCRIPTION OF THE EMBODIMENTS
[0037] Reference will now be made in detail to the present
preferred embodiments of the disclosure, examples of which are
illustrated in the accompanying drawings.
[0038] Wherever possible, the same reference numbers are used in
the drawings and the description to refer to the same or like
parts.
[0039] The disclosure is further described below with reference to
specific embodiments.
[0040] Comparative example: direct plasma sintering is performed on
atomized powder to prepare Rene 104 nickel-based high-temperature
alloy.
[0041] Plasma sintering is performed on gas atomized Rene 104
nickel-based pre-alloyed powder (components are
Ni-13Co-16Cr-4Mo-4W-2.2Al-3.7Ti-0.77Nb (wt %)); processing
parameters are: 1150.degree. C./40 MPa/heat preservation for 5 min,
and then solution treatment is performed; the solution treatment is
performed at 1180.degree. C. for 1 h, and furnace cooling is
performed; and then aging treatment s performed at 815.degree. C.
for 8 h to obtain a nickel-based high-temperature alloy.
[0042] FIG. 1 is a microscopic structure of Rene 104 nickel-based
high-temperature alloy prepared in this comparative example, and
obvious prior particle boundaries can be observed. See parts
indicated by 1 and 2 in FIG. 1.
Embodiment 1
[0043] Gas atomized Rene 104 nickel-based pre-alloyed powder is put
into a ball mill pot with a ball-to-powder ratio of 10:1, and ball
milling is performed in a planetary ball mill for 1.5 h at a ball
milling rotation speed of 250 r/min under protection of argon, to
obtain ball milling nickel-based high-temperature alloy powder.
[0044] Plasma sintering is performed on ball milling nickel-based
high-temperature alloy powder at 1150.degree. C./40 MPa, and heat
preservation is performed for 5 min, then solution treatment is
performed; the solution treatment is performed at 1180.degree. C.
for 1 h, and furnace cooling is performed; then, aging treatment is
performed at 815.degree. C. for 8 h to obtain a nickel-based
high-temperature alloy.
[0045] FIG. 2 is a scanning electronic microscope (SEM) diagram of
a cross section of atomized powder of the present embodiment, and
obvious hollow defects occur to some powder in FIG. 2. See parts
indicated by 3, 4, 5, and 6 in FIG. 2. FIG. 3 is an SEM diagram of
a cross section of powder after mechanical ball milling is
performed on atomized powder in the present embodiment, and no
powder hollow phenomenon is observed. FIG. 4 is a metallographic
microscopic structure of a nickel-based powder high-temperature
alloy prepared in the present embodiment, and no obvious prior
particle boundaries are observed.
Embodiment 2
[0046] Gas atomized Rene 104 nickel-based pre-alloyed powder is put
into a ball mill pot, and ball milling is performed in a stirring
ball mill for 3 h at a ball milling rotation speed of 100 r/min
under protection of argon, to obtain ball milling nickel-based
high-temperature alloy powder.
[0047] Ball milling powder is put into a steel capsule; vacuuming
and sealing welding are performed on the steel capsule; hot
extrusion forming is performed at 1100.degree. C. with an extrusion
ratio of 10:1 to obtain a highly compact nickel-based alloy bar;
finally, solution treatment is performed at 1115.degree. C. for 1 h
and performed at 1170.degree. C. for 3 h and air cooling is
performed; aging treatment is performed at 845.degree. C. for 4 h
and performed at 760.degree. C. for 8 h and air cooling is
performed, to obtain a nickel-based high-temperature alloy.
[0048] It will be apparent to those skilled in the art that various
modifications and variations can be made to the structure of the
present disclosure without departing from the scope or spirit of
the disclosure. In view of the foregoing, it is intended that the
present disclosure cover modifications and variations of this
disclosure provided they fall within the scope of the following
claims and their equivalents.
* * * * *