U.S. patent application number 16/524354 was filed with the patent office on 2019-11-21 for aluminum substrates with metal-matrix composite at feature areas.
This patent application is currently assigned to NATIONAL RESEARCH COUNCIL OF CANADA. The applicant listed for this patent is NATIONAL RESEARCH COUNCIL OF CANADA. Invention is credited to Yangsheng Li, Shaodong Wang, Lijue Xue.
Application Number | 20190351486 16/524354 |
Document ID | / |
Family ID | 45496405 |
Filed Date | 2019-11-21 |
United States Patent
Application |
20190351486 |
Kind Code |
A1 |
Xue; Lijue ; et al. |
November 21, 2019 |
ALUMINUM SUBSTRATES WITH METAL-MATRIX COMPOSITE AT FEATURE
AREAS
Abstract
A substrate has a body defined at least in part by a single
piece of aluminum or aluminum alloy material having a cavity and a
pinch-off or other feature area and further having a metal-matrix
composite (MMC) layer formed integrally in the body at the
pinch-off or other feature area. A process of producing a substrate
involves machining a single piece of material to provide a body
having a surface and a feature area, the feature area being of
smaller dimension than required for the piece, integrally forming a
metal-matrix composite layer in the feature area to build up the
feature area to at least a dimension required for the piece. The
metal-matrix composite comprises an aluminum-nickel alloy matrix
(e.g. Al-12Si alloy alloyed with Ni) having WC particles embedded
therein or a aluminum matrix (e.g. Al-12Si alloy) having TiC
particles embedded therein and has greater wear resistance, greater
strength, greater toughness or any combination thereof than the
material.
Inventors: |
Xue; Lijue; (London, CA)
; Wang; Shaodong; (London, CA) ; Li;
Yangsheng; (London, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NATIONAL RESEARCH COUNCIL OF CANADA |
Ottawa |
|
CA |
|
|
Assignee: |
NATIONAL RESEARCH COUNCIL OF
CANADA
Ottawa
CA
|
Family ID: |
45496405 |
Appl. No.: |
16/524354 |
Filed: |
July 29, 2019 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13811407 |
Jan 22, 2013 |
10363605 |
|
|
16524354 |
|
|
|
|
12886936 |
Sep 21, 2010 |
|
|
|
PCT/CA2011/000838 |
Jul 21, 2011 |
|
|
|
13811407 |
|
|
|
|
61366740 |
Jul 22, 2010 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 2049/4892 20130101;
B29C 49/04 20130101; B29C 2049/4897 20130101; B29C 49/4823
20130101; B29L 2031/7158 20130101; B29C 49/48 20130101; B29C 49/06
20130101; B29C 33/38 20130101; B29C 33/56 20130101; B29C 2049/4874
20130101; B29K 2905/02 20130101; B22F 5/007 20130101 |
International
Class: |
B22F 5/00 20060101
B22F005/00; B29C 33/56 20060101 B29C033/56 |
Claims
1. A substrate, composed of Al or an alloy thereof, with a cladding
of a wear resistant metal matrix ceramic (MMC) comprising: a Ni
bearing Al alloy matrix with particles of WC; or an Al matrix with
particles of TiC, where the cladding is metallurgically bonded to
the substrate, and the WC or TiC particles are distributed in the
matrix in an amount in a range of from 5 to 50%, based on a weight
of the composite.
2. The substrate according to claim 1 wherein the Al alloy of which
the substrate is composed comprises: Al 2024 all, Al 2124 all, Al
2219 T31 through T87, Al 6009 all, Al 6010 all, Al 6061 T4 through
T6511, Al 7075 T6 through T7351, Al 7050 all or Al 7475 all.
3. The substrate according to claim 2 wherein the Al alloy of which
the substrate is composed comprises Al 7075 T6 through T7351.
4. The substrate according to claim 1 wherein the substrate is clad
at feature areas thereof and not at a surface of the substrate away
from the feature areas, whereby the cladding is not a coating.
5. The substrate according to claim 1 wherein the matrix comprises
Al-1251 alloy.
6. The substrate according to claim 1 wherein the matrix comprises
Al 4047.
7. The substrate according to claim 1 wherein the WC or TiC
particles are distributed in the matrix in an amount in a range of
from 10 to 40%, based on the weight of the composite.
8. The substrate according to claim 1 wherein the WC or TiC
particles are distributed in the matrix in an amount in a range of
from 20 to 35%, based on the weight of the composite.
9. The substrate according to claim 1 wherein the MMC layer has a
microstructure consistent with formation by laser cladding.
10. The substrate according to claim 1 wherein cladding has a wear
resistance of at least about 5 times that of the substrate.
11. The substrate according to claim 1 wherein the cladding
comprises WC particles.
12. The substrate according to claim 11 wherein the cladding has a
Vickers hardness (Hv0.5) of about 200.
13. The substrate according to claim 11 wherein the matrix
comprises 1.5-5.4% Ni based on weight of the composite.
14. The substrate according to claim 11 wherein the matrix
comprises 2.4-3.6% Ni based on weight of the composite.
15. The substrate according to claim 11 wherein the matrix
comprises about 3% Ni based on weight of the composite.
16. The substrate according to claim 11 wherein the embedded
particles are distributed in the aluminum-nickel alloy matrix in an
amount of about 27%, based on the weight of the composite.
17. The substrate according to claim 1 wherein the cladding
comprises TiC particles.
18. The substrate according to claim 17 wherein the cladding has
the embedded particles distributed in the aluminum-nickel alloy
matrix in an amount of about 30%, based on the weight of the
composite.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is continuation of, and claims priority
under 35 U.S.C. .sctn. 120 to, U.S. application Ser. No.
13/811,407, filed Jan. 22, 2013, which is continuation-in-part of,
and claims priority under 35 U.S.C. .sctn. 120 to, U.S. application
Ser. No. 12/886,936, filed on Sep. 21, 2010, which was a U.S.
National Stage of, filed under 35 U.S.C. .sctn. 371 of
PCT/CA2011/000838, filed on Jul. 21, 2011, which claims benefit of
U.S. Provisional App. No. 61/366,740, filed on Jul. 22, 2010, the
entire contents of which are herein incorporated by reference
herein.
FIELD OF THE INVENTION
[0002] The present invention relates to aluminum substrates clad
with metal matrix composites.
BACKGROUND OF THE INVENTION
[0003] Aluminum alloys are typically used to make blow mold halves,
mold halves for other forming, and substrates in general for
tooling or parts, due to their good thermal conductivity, light
weight and ease of machining. However, aluminum alloys are usually
soft and have relatively inferior wear resistance. In order to
extend life, inserts made of hard and tough metals (typically,
beryllium-copper or hardened steel) are sometimes used at areas
that provide special features in the aluminum (FIG. 1). However,
these inserts have to be machined separately from and fastened onto
the substrates, which significantly increases the complexity of the
design and increases production cost and time for manufacturing and
assembling of these inserts. Due to the addition of these inserts,
cooling channels may have to be designed beneath the inserts, which
may restrict the effectiveness of the cooling. In addition,
beryllium-copper material typically used to make these inserts is
quite expensive and more difficult to machine.
[0004] One-piece aluminum substrates that eliminate insert segments
(FIG. 2) simplify design, as they reduce the effort expended to
ensure that the various inserts align properly with one another
upon assembly. One-piece aluminum substrates may be constructed
relatively quickly, as compared to substrates with insert segments,
and at low cost. Heat transfer performance is also enhanced over
segmented substrates, as thermal breaks formed by the junctions of
aligned parts are eliminated.
[0005] Methods are known that use explosive cladding (or roll
cladding, diffusion bonding, etc.) to metallurgically bond a very
hard metal layer (such as steel, titanium, etc.) to a softer but
very thermally conductive metal substrate (such as an aluminum
alloy). One problem with technologies such as these is that the
layer of very hard metal has different thermal properties than the
substrate leading to cracking, especially under prolonged usage.
Extra layers of other thermally conductive material may be employed
to mitigate against cracking, but this complicates the process and
does not satisfactorily address the cracking problem.
[0006] Prior to the making of this invention, it was not known what
materials can metallurgically bond to Al or Al-alloy substrates to
improve wear resistance, without cracking, peeling, or
decomposition of the ceramic during cladding. There remains a need
in the art for further improvement to aluminum substrates with
layers of metal-matrix composite at feature areas.
SUMMARY
[0007] Thus, there is provided a part or piece comprising a body
defined at least in part by a single piece of aluminum or aluminum
alloy material comprising a surface and a feature area and further
comprising a layer of a metal-matrix composite (MMC) formed
integrally therein at the feature area, the MMC comprising an
aluminum-nickel alloy matrix having WC particles embedded therein
or an aluminum matrix having TiC particles embedded therein.
[0008] There is further provided a process of producing a piece
comprising: machining a single piece of aluminum or aluminum alloy
material to provide a body comprising a surface and a feature area,
the feature area being of smaller dimension than required for the
piece; and integrally forming a layer of a metal-matrix composite
(MMC) in the feature area to build up the feature area to at least
a dimension required for the aluminum substrate, the MMC comprising
an aluminum-nickel alloy matrix having WC particles embedded
therein or an aluminum matrix having TiC particles embedded
therein.
[0009] A layer of the MMC may be formed integrally in one, or more
feature areas.
[0010] The MMC layer comprises an aluminum matrix. For the aluminum
matrix, aluminum alloys are particular useful, for example Al 2024
all, Al 2124 all, Al 2219 T31 through T87, Al 6009 all, Al 6010
all, Al 6061 T4 through T6511, Al 7075 T6 through T7351, Al 7050
all and Al 7475 all. Al-12Si alloys are particularly preferred.
Al-12Si alloys are identified in the art as Al 4047 and comprise
aluminum alloyed with about 11-13 wt % (nominally about 12 wt %)
silicon, based on total weight of the alloy. Embedded in the
relatively soft aluminum matrix are hard and wear resistant
particles of a tungsten carbide (WC) or titanium carbide (TiC).
When WC particles are embedded, the aluminum matrix is an
aluminum-nickel alloy matrix. When TiC particles are embedded, the
aluminum matrix is a matrix without alloyed nickel.
[0011] The nickel in the aluminum-nickel alloy matrix may be
alloyed with the aluminum alloy prior to embedding the tungsten
carbide (WC) particles, or more preferably, during the embedding
process. During the embedding process, a WC/Ni material may be used
in which the nickel acts as a binder for the WC particles in the
material. During the embedding process, the nickel is melted and
dissolves in the aluminum alloy to form the aluminum-nickel alloy
matrix while the WC particles are only partially melted and remain
as hard particulates embedded in the matrix. The Ni that dissolves
in the aluminum alloy interacts with the aluminum alloy to form
intermetallics that further increase matrix hardness.
[0012] WC or TiC particles are embedded in the matrix in any amount
suitable to provide sufficiently greater wear resistance, strength
and/or toughness at the feature areas to satisfactorily extend the
working life of the piece. The amount of WC or TiC distributed in
the matrix is preferably in a range of from about 5 wt % to about
50 wt %, based on the weight of the composite, more preferably
about 10-40 wt %, for example about 20-35 wt %. When used, the
amount of nickel alloyed in the matrix of the composite is
preferably in a range of from about 1.5 wt % to about 5.5 wt %,
based on the weight of the composite, more preferably about 2.4-3.6
wt %, for example about 3 wt %.
[0013] The MMC layer has greater wear resistance, strength and/or
toughness than the aluminum or aluminum alloy into which the MMC is
integrally formed, thereby providing greater resistance to high
pressures and mechanical stresses. Further, the MMC layer has good
bonding and compatibility to the material so that the interface and
surrounding areas will not induce crack or peel-off. The MMC has a
similar coefficient of thermal expansion compared to the material,
which reduces the likelihood of cracking or other damage to the
aluminum substrate due to changes in temperature.
[0014] The material comprises aluminum or an aluminum alloy. Some
examples of suitable aluminum alloys include Al 2024 all, Al 2124
all, Al 2219 T31 through T87, Al 6009 all, Al 6010 all, Al 6061 T4
through T6511, Al 7075 T6 through T7351, Al 7050 all and Al 7475
all. It should be noted that all aluminum alloys have excellent
thermal properties but other materials with high strength and
heat-treated properties are generally chosen when improved wear,
strength and thermal properties are necessary in combination.
[0015] The MMC layer may be formed in the feature area by any
suitable process. The MMC layer may be formed by adding the MMC
material to, or by otherwise modifying the surface of, the body in
the feature area. In some instances, it may be desirable to form
the MMC layer in different feature areas using different processes.
The process or processes used to add and/or modify the feature area
are preferably very well controlled so that the features are
accurately engineered at the desired locations and are integrally
formed in the body, e.g. by metallurgical bonding. Preferably, the
process has minimal effect on the material in order to reduce
potential distortion and property deterioration of the body.
Thickness of the MMC layer depends on working conditions and the
process used to create the layer. For example, thicknesses may be
from about several nanometers to several tens of millimeters.
[0016] In one preferred embodiment, an MMC layer may be formed by
first engineering a body in which feature area is machined to an
undersized dimension, and then adding MMC material to the feature
area to build up the feature to final dimension. In a variation of
this embodiment, the feature area may be built up with MMC material
beyond final dimension and then machined down to final
dimension.
[0017] There is also provided a substrate, composed of Al or an
alloy thereof, with a cladding of a wear resistant metal matrix
ceramic (MMC) comprising: a Ni bearing Al matrix with particles of
WC; or an Al matrix with particles of TiC, where the cladding is
metallurgically bonded to the substrate, and the WC or TiC
particles are distributed in the matrix in an amount in a range of
from 5 to 50%, based on a weight of the composite.
[0018] The substrate may comprise Al 2024 all, Al 2124 all, Al 2219
T31 through T87, Al 6009 all, Al 6010 all, Al 6061 T4 through
T6511, Al 7075 T6 through T7351, Al 7050 all or Al 7475 all. More
preferably, the substrate may comprise Al 7075 T6 through
T7351.
[0019] The matrix may comprise Al-12Si alloy. The WC or TiC
particles may be distributed in the matrix in an amount in a range
of from 10 to 40 wt %, or 20 to 35 wt %, based on the weight of the
composite. The MMC layer may be formed by laser cladding.
[0020] The cladding may have a wear resistance of at least about 5
times that of the substrate.
[0021] If the cladding is the MMC with WC particles, the cladding
may have: a Vickers hardness (Hv0.5) of about 200; within the
matrix, 1.5-5.4%, more preferably 2.4-3.6%, and more preferably
about 3%, Ni based on weight of the composite; the embedded
particles distributed in the aluminum-nickel alloy matrix in an
amount of about 27%, based on the weight of the composite.
[0022] If the cladding is the MMC with TiC particles, the cladding
may have the embedded particles distributed in the aluminum-nickel
alloy matrix in an amount of about 30%, based on the weight of the
composite.
[0023] Various processes may be used to form the MMC layer. Such
processes include, for example, laser cladding, laser alloying,
electron beam cladding, electron beam alloying, brazing, diffusion
bonding, friction stir welding, laser assisted thermal spray, laser
assisted cold spray, low heat input welding (e.g. micro plasma
welding), aluminum anodizing, ion implantation, chemical vapor
deposition, plasma enhanced physical vapor deposition, diffusion
coating, plasma treating, electroplating and electroless
plating.
[0024] Laser cladding is a process that enables metallurgical
bonding of MMC material to the body to build up a relatively thick
layer of the MMC layer in the feature area. Compared to
conventional welding, laser cladding involves much better control
and much less heat input, which reduces distortion and property
deterioration in the body. As a variation, laser alloying may be
used to melt the surface layer of the body to permit addition of
various alloying elements to enhance surface hardness and wear
resistance in the feature area. In another variation, an electron
beam may be used instead of or in addition to a laser as the
heating source for cladding.
[0025] In the present invention, the feature areas are built up
and/or enhanced with a specifically engineered MMC material. The
specific requirements for each feature area can be met by tailoring
the specifically engineered MMC material without affecting the
material used to make bodies. Metallurgical bonding between the MMC
material and the material offers good compatibility between the two
materials, which ensures long life of the feature areas during high
pressure and high cycle rate operations.
[0026] Further, parts having a very hard metal layer (such as
steel, titanium, etc.) metallurgically bonded to a softer but very
thermally conductive aluminum or aluminum alloy substrate suffer
from thermal incompatibility between the cladding layer and the
body leading to cracking, thereby shortening the effective working
life. The present aluminum substrates combine wear resistance,
strength and/or toughness with good thermal compatibility at the
feature areas to provide significantly extended working lives.
[0027] Furthermore, the present invention may be used not only on
flat parting surfaces but may also be advantageously used on
contoured parting surfaces. There is no restriction on substrate
size. The present invention may be used to produce any article that
may be formed. Some examples of articles include containers (e.g.
bottles), automotive components, recreational components,
industrial components and chemical components, especially
containers.
[0028] Further features of the invention will be described or will
become apparent in the course of the following detailed
description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] In order that the invention may be more clearly understood,
embodiments thereof will now be described in detail by way of
example, with reference to the accompanying drawings, in which:
[0030] FIG. 1 is a schematic drawing of a traditional substrate
with insert segments;
[0031] FIG. 2 is a schematic drawing of a substrate in accordance
with U.S. Pat. No. 7,531,124;
[0032] FIG. 3 is a schematic drawing of one embodiment of a
substrate pre-machined to an undersized shape at feature areas;
[0033] FIG. 4 is a schematic drawing of one embodiment of a
metal-matrix composite (MMC) layer integrated on to the substrate
of FIG. 3 at the feature areas, where FIG. 4A shows the MMC layer
with an initial excess of MMC material and FIG. 4B shows the MMC
layer after being machined to final dimension;
[0034] FIG. 5 is a schematic drawing of a substrate of the present
invention having a metal-matrix composite layer integrated at
feature areas;
[0035] FIG. 6A depicts microstructure of a cross-section of a Al
7075-T651 substrate clad with a Al 4047+30% (90% WC+10% Ni)
metal-matrix composite layer;
[0036] FIG. 6B depicts microstructure of a cross-section of a Al
7075-T651 substrate clad with a Al 4047+30% (TiC) metal-matrix
composite layer;
[0037] FIG. 7 depicts a graph showing hardness depth profile of Al
4047+30% (90% WC+10% Ni) metal-matrix composite layer clad on Al
7075-T651 substrate;
[0038] FIG. 8 depicts a graph comparing Vickers hardness of Al
4047+30% (90% WC+10% Ni) metal-matrix composite layer to that of Al
7075-T651, A2 steel, Be--Cu alloy and Stainless Steel Stavex ESR;
and,
[0039] FIG. 9 depicts a graph comparing wear loss of Al 4047+30%
(90% WC+10% Ni) and Al 4047+30% (TiC) metal-matrix composite layer
to that of Al 7075-T651, A2 steel, Be--Cu alloy and Stainless Steel
Stavex ESR.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0040] FIG. 1 depicts a traditional substrate for a bottle blow
mold in which insert segments are used in the pinch-off and other
feature areas. Thus, substrate 10 has a body 11 having cavity 12.
Pinch-off insert segment 14 comprising raised pinch-off area 15 is
inserted into pinch-off insert area 13 of the body and secured to
the body by bolts. Bottle top thread insert 17 comprising raised
thread feature 18 and bottle top insert 19 comprising raised bottle
top feature 20 are inserted into bottle top feature insert area 16
of the body and secured to the body by bolts. Bottle shoulder
insert 22 comprising raised shoulder feature 23 is inserted into
shoulder insert area 29 of the body and secured to the body by
bolts.
[0041] FIG. 2 depicts a substrate for a bottle blow mold in
accordance with U.S. Pat. No. 7,531,124. Substrate 30 includes a
body 31 having cavity 32, raised pinch-off area 35, raised thread
feature 38, raised bottle top feature 40 and raised shoulder
feature 43. The body, pinch-off area and all three features
comprise the same material.
[0042] FIGS. 3-5 depict one embodiment of a substrate for a bottle
blow mold in accordance with the present invention at various
stages of fabrication. Referring to FIG. 3, substrate 50 comprising
aluminum alloy body 51 and cavity 52 is pre-machined to an
undersized shape at pinch-off area 53, thread feature area 56,
bottle top feature area 57 and shoulder feature area 59. Referring
to FIG. 4A, in order to complete the substrate, a layer of MMC
material is laser clad at pinch-off area 53 (and the other feature
areas not shown in FIG. 4) to provide raised layer 70 of the
cladding material having excess portion 71. In order to avoid
undercut and/or mismatch, body 51 at each side of raised layer 70
is rough machined prior to the laser cladding step to leave spare
layer 72 of material at each side of raised layer 70. After the
cladding step, spare layer 72 is machined off along with excess
portion 71 of the cladding material to bring body 51 and raised
layer 70 to final dimension (FIG. 4B). For certain processes, the
spare layer may not be necessary provided no undercut and/or
mismatch between the MMC material and the body occurs. Referring to
FIG. 5, after cladding, substrate 50, having body 51 and cavity 52,
comprises clad pinch-off area 55 and clad other feature areas 58,
60 and 63 in which an MMC layer is integrally formed.
Example 1: Laser Cladding of Al 7075-T651 Substrate with Al
4047+WC/Ni
[0043] Laser cladding was performed by using a focused Nd:YAG laser
beam with a 115-mm focal length lens. A powder feeder was used to
simultaneously deliver Al 4047 and WC/Ni powder mixture through a
feed nozzle into the melt pool at a rate of about 2 g/min. The
laser beam and powder feeding nozzle were kept stationary, while
the Al-7075-T561 substrate was moved under the beam by a CNC motion
system. The cladding was conducted with an average laser power up
to 500 W with a beam diameter of about 1 mm. A laser pulse duration
of 10 ms and a frequency of 10 Hz were used for the processing. An
overlap ratio of 30% was used between passes to produce
multi-passes to cover the required area, while a z movement of
about 130 .mu.m was used to deposit multi-layers to reach the
required height.
Example 2: Laser Cladding of Al 7075-T651 Substrate with Al
4047+TiC
[0044] Laser cladding was performed by using a focused Nd:YAG laser
beam with a 115-mm focal length lens. A powder feeder was used to
simultaneously deliver Al 4047 and TiC powder mixture through a
feed nozzle into the melt pool at a rate of about 2 g/min. The
laser beam and powder feeding nozzle were kept stationary, while
the Al-7075-T561 substrate was moved under the beam by a CNC motion
system. The cladding was conducted with an average laser power up
to 500 W with a beam diameter of about 1 mm. A laser pulse duration
of 10 ms and a frequency of 10 Hz were used for the processing. An
overlap ratio of 30% was used between passes to produce multi
passes to cover the required area, while a z movement of about 200
.mu.m was used to deposit multi-layers to reach the required
height.
Example 3: Microstructure Analysis of Clad Substrates
[0045] In a preliminary experiment, a layer of Al 4047 (which is
the matrix material of the metal-matrix composite) was laser clad
on to Al 7075-T651 substrate by a modification of the procedure of
Example 1 in order to examine the microstructure of the clad
specimen. This was compared to a similar specimen in which a layer
of Al 7075 was clad on to Al 7075-T651 substrate. Examination by
optical microscopy of a cross-section of the specimens showed that
cladding with Al 7075 showed a tendency for cracking while cladding
with Al 4047 produce a good metallurgical bond without inducing
cracks or pores in the clad layer. Further, the laser clad Al 4047
layer showed good machinability, a smooth transition of hardness
from the substrate to the clad layer, and a generally uniform
hardness through the layer. Finally, a polishing test showed that
the laser clad Al 4047 layer is superior to the Al 7075-T651
substrate in polishing.
[0046] With reference to FIG. 6A, microstructure analysis was
extended to a metal-matrix composite (MMC) in which Al 4047+30%
(90% WC+10% Ni) MMC layer 100 was laser clad on to Al 7075-T651
substrate 101 in accordance with the process in Example 1. The MMC
comprises WC particles embedded in an Al 4047/Ni matrix formed
using 30 wt % WC/Ni material. The WC/Ni material consists of 90 wt
% WC (tungsten carbide) and 10 wt % Ni (nickel). Thus, the amount
of WC in the MMC layer is about 27 wt % and the amount of nickel
alloyed with the Al 4047 is about 3 wt %, based on the weight of
the MMC. A good metallurgical bond was formed with no formation of
cracks or pores in the MMC layer. Further, in the MMC layer, WC
hard particles 102 were evenly distributed in Al 4047/Ni matrix
103, while the Ni from the WC/Ni material dissolved in the Al 4047
to form intermetallics that further increase matrix hardness.
Similar experiments were performed with other metal-matrix
composites, i.e. Al 4047+Al.sub.2O.sub.3 and Al 4047+WC/Co. In the
case of Al 4047+Al.sub.2O.sub.3, laser cladding did not generate
hardening, probably due to the decomposition of Al.sub.2O.sub.3
during the cladding process. In the case of Al 4047+WC/Co, the clad
layer had improved wear resistance but showed a tendency to
crack.
[0047] With reference to FIG. 6B, microstructure analysis was
extended to a metal-matrix composite (MMC) in which Al 4047+30%
(TiC) MMC layer 200 was laser clad on to Al 7075-T651 substrate 201
in accordance with the process in Example 2. The MMC comprises TiC
particles embedded in an Al 4047 matrix formed using 30 wt % TiC
material. A good metallurgical bond was formed with no formation of
cracks or pores in the MMC layer. Further, in the MMC layer, TiC
hard particles 202 were evenly distributed in Al 4047 matrix
203.
Example 4: Microhardness Analysis of Clad Substrates
[0048] A Vickers hardness test (ASTM E384--10e2) was conducted on
the laser clad products of Examples 1 and 2 using a load of 500 g
for 15 s at evenly distributed points spaced by 0.2 mm. FIG. 7
depicts hardness depth profile of the Al 4047+30% (90% WC+10% Ni)
MMC layer clad on the Al 7075-T651 substrate. It is evident from
FIG. 7 that the Al 4047+30% (90% WC+10% Ni) is harder than the Al
7075-T651 substrate. The substrate near the clad layer has a
softening zone with a Vickers hardness (Hv0.5) of around 140,
perhaps due to annealing induced by laser cladding. There was a
larger deviation in the hardness of laser clad (Al 4047+30% (90%
WC+10% Ni)) layer due to heterogeneous features in the MMC.
[0049] Further, with reference to FIG. 8, Vickers hardness of the
Al 4047+30% (90% WC+10% Ni) MMC layer was compared to that of the
Al 7075-T651 and other typical insert materials (i.e. A2 steel,
Be--Cu alloy and Stainless Steel Stavex ESR). Table 1 summarizes
the results and includes the hardness of the Al 4047+30% (TiC) MMC
layer. Table 1 and FIG. 8 demonstrate that the Al 4047+30% (90%
WC+10% Ni) layer is harder than Al 7075-T651 and approaches that of
the steels. Table 1 demonstrates that the Al 4047+30% (TiC) layer
is somewhat softer than Al 7075-T651.
TABLE-US-00001 TABLE 1 Vickers Hardness Material Vickers Hardness
(Hv0.5) A2 steel 222 Be-Cu alloy 384 Stainless Steel Stavex ESR 231
Al 4047 + 30% (90% WC + 10% Ni) 198 Al 4047 + 30% (TiC) 141 Al
7075-T651 177
Example 5: Wear Resistance Analysis of Clad Substrates
[0050] Wear resistance was performed with pin-on-disc testing as
per ASTM G99-05 (2010) to evaluate sliding wear resistance of a
laser-clad specimen of the present invention (Al 4047+30% (90%
WC+10% Ni) on Al 7075-T651; Al 4047+30% (TiC) on Al 7075-T651) in
comparison to Al 7075-T651, A2 steel, Be--Cu and Stainless Steel
Stavex ESR. The test was performed with a Falex Pin-on-Disc Tester
with a dry slide to determine volume wear loss. All sample surfaces
were fine ground and cleaned before testing. The testing was done
with a normal load of 3.5 N, at a linear slide speed of 300 mm/s
over a total slide distance of 1500 m using a 1/4'' tungsten
carbide (WC) ball.
[0051] Wear loss results from the pin-on-disc testing are shown in
FIG. 9 and summarized in Table 2. Using wear of Al 7075-T651
substrate as a reference, relative wear resistance (R) was
calculated by dividing volume wear loss of Al 7075-T651 by volume
wear loss of the other materials. Wear resistances of the clad Al
4047+30% (90% WC+10% Ni) and Al 4047+30% (TiC) in accordance with
the present invention are significantly better (5.28 and 4.99
times, respectively) than that of the Al-7075-T651 substrate. The
wear resistances of the Al 4047+30% (90% WC+10% Ni) and Al 4047+30%
(TiC) layers are similar to that of Stavex Stainless Steel. The
wear resistances of the Al 4047+30% (90% WC+10% Ni) and Al 4047+30%
(TiC) layers are close to but still relatively inferior to that of
Be--Cu.
TABLE-US-00002 TABLE 2 Wear Loss Volume Wear Loss Relative Wear
Material (10.sup.-3 mm.sup.3/m) Resistance (R) A2 steel 0.085 17.1
Be-Cu alloy 0.157 9.27 Stainless Steel Stavex ESR 0.251 5.80 Al
4047 + 30% (90% WC + 0.276 5.28 10% Ni) Al 4047 + 30% (TiC) 0.292
4.99 Al 7075-T651 1.456 1
[0052] Cladding of an aluminum or aluminum alloy substrate with a
Al 4047+30% (90% WC+10% Ni) or Al 4047+30% (TiC) metal-matrix
composite provides an excellent balance of properties. The clad
metal-matrix composite layer forms a good metallurgical bond with
the substrate with no formation of cracks or pores. Excellent
hardness and wear resistance for Al 4047+30% (90% WC+10% Ni),
approaching that of materials used in the prior art, and excellent
wear resistance for Al 4047+30% (TiC) leads to extended life at
feature areas, while good thermal compatibility between the
substrate and metal-matrix composite layer makes the MMC layer less
prone to cracking further extending the life. Good machinability
provides for ease of manufacturing.
[0053] In contrast, Al 7075-T651 itself is soft and easily worn,
therefore its use at feature areas in substrates results in reduced
service life. Use of typical hard, wear resistant materials such as
steels and Be--Cu alloy at feature areas extends working life of
aluminum or aluminum alloy substrates, but is still unsatisfactory
since thermal incompatibility leads to cracking which prevents a
full realization of the benefits of the harder material. Further,
such hard, wear resistant materials are difficult to machine, which
makes manufacturing more difficult.
REFERENCES
[0054] The contents of the entirety of each of which are
incorporated by this reference. [0055] Dickinson A, et al. (1991)
"Process for forming an extrusion-blow molded ultrathin container
using a heat generating pinch off arrangement". U.S. Pat. No.
5,021,209 issued Jun. 4, 1991. [0056] Kobayashi S. (1996) "Blow
molding die and method of manufacturing same". European Patent
Publication 742,094 published Nov. 13, 1996. [0057] Lee N. (2007)
"Understanding blow molding". Hanser Publications, p. 61-70. [0058]
Paget T. (2009) "One-piece blow mold halves for molding a
container". U.S. Pat. No. 7,531,124 issued May 12, 2009.
[0059] Other advantages that are inherent to the structure are
obvious to one skilled in the art. The embodiments are described
herein illustratively and are not meant to limit the scope of the
invention as claimed. Variations of the foregoing embodiments will
be evident to a person of ordinary skill and are intended by the
inventor to be encompassed by the following claims.
* * * * *