Development of AlBeMet® Extruded Products
Charles Pokross & Adam Carr, Materion Beryllium & Composites
ABSTRACT
Materion Beryllium & Composites has developed new powder metallurgy extrusion technology which resulted in successful
extrusion of a 10-in. (25-cm) diameter x 240-in. (610-cm) long AlBeMet® 162 circular cylinder. AlBeMet® is a family of
aluminum-beryllium compositions which contain 20-75 weight percent Be in an aluminum matrix. Input powder for the 10-in
(25-cm) diameter extrusion was inert-gas atomized Al-62wt. % Be, AM162. The powder was cold isostatically pressed (CIP)
into 4 quarter round segments, encapsulated in a copper can, sealed and extruded to a solid final shape. Extrusion was
performed on a 35,000-ton (311-MN) vertical extrusion press. The results of micro-structural analysis and mechanical property
testing of the extrusion are included. Following discussion of the 10-in (25-cm) diameter extrusion, a summary of a project to
extrude more complex shapes from AlBeMet® metal matrix composites is presented.
INTRODUCTION
AlBeMet® is family of aluminum-beryllium compositions manufactured by Materion Beryllium & Composites which contain 2075 weight percent Be in an aluminum matrix. AlBeMet® combines the high modulus and low density attributes of beryllium with
the ease of fabrication offered by aluminum. The AM162 grade of AlBeMet® is primarily used for avionic applications; other
grades of AlBeMet® are used in a wide variety of components such as computer hard drive actuator arms and high performance
sporting goods.
The objective of extruding a 10-in. (25-cm) diameter round was to provide customers with a large cross section product
exhibiting mechanical properties superior to hot isostatically pressed (HIP) powder. Although shapes of this size could be
manufactured by HIP, the resulting mechanical properties are inferior to extruded product. The challenges were to utilize
existing equipment and facilities to manufacture a large diameter extrusion billet; and to extrude a round which met the
physical and mechanical property values of production extrusions.
For a majority of extruded products, the AlBeMet® powder process is comprised of the following steps: consolidate powder
billet to 85% theoretical density by CIP; encapsulate in copper; and extrude with at least a 4:1 reduction ratio. A flow chart of
the powder extrusion process is shown in Figure 1. Input powder for the 10-in (25-cm) diameter extruded round was AM162;
a typical chemistry is presented in Table 1.
Figure 1. Process diagram for extruded AM162.
Atomization
Blending
CIP
Canning
Testing
Heat Treat
Decanning
Extrusion
MAAB-010
MATERION BERYLLIUM & COMPOSITES
``
14710 W Portage River South Rd
Elmore, OH 43416-9502
p: +1 419.862.4533 or +1 419.862.4171 Intl: +1 419.862.4127
e: [email protected]
MAAB-009
MATERION CORPORATION
www.materion.com/beryllium
© Materion Corporation
Table 1. Typical AM162 Chemistry
Be (%)
O2 (%)
C (%)
Al
Fe (ppm)
61.25
0.19
0.059
Bal.
Si (ppm)
1090
410
Cu (ppm)
115
Ti (ppm)
1010
Extruding a 10-in. (25-cm) diameter bar which met or exceeded the minimum reduction ratio required a CIP billet 27-in (69cm) in diameter. Encapsulating the billet in copper resulted in a total assembly diameter close to 30-in (76-cm). AM162
extrusion data was used to estimate a force of approximately 22,000 tons (196 MN) to extrude the assembly. A 35,000 ton
(311 MN) vertical extrusion press which met the load and size requirements was located at Wyman-Gordon Forgings Inc.,
(WGF) Houston, Texas.
The CIP unit at Materion Beryllium & Composites’ Elmore, Ohio facility is capable of consolidating a maximum 19-in (48cm)
diameter billet; therefore, an unconventional processing method was developed: CIPing four quarter round segments to form
the 27-in (69-cm) diameter billet. A three-phase program was initiated to prove feasibility for this billet preparation method,
and to confirm that WGF's tooling and lubrication systems did not substantially affect the extrusion characteristics of
AM162.The objectives of the program were three-fold; Phase I: prove that four CIP'd segments could be extruded to a 100%
dense and integral shape; Phase II: prove the extruder's tooling configuration and lubrication; Phase III: prove that a 30-in (76cm) segmented billet could be successfully extruded to a 10-in (25-cm) diameter round and meet typical AM 162 extruded and
annealed properties.
The large cross section extrusion offers designers of bulk components the advantages of AlBeMet®'s high specific strength and
specific modulus, but these properties are equally important to designers of small, complex extruded shapes. The intricate
design features which maximize the mechanical and physical properties of AlBeMet® often require costly post-extrusion
machining or forming operations to complete. The objective of the complex extrusion program is to reduce or eliminate postextrusion operations by directly extruding net- or near-net shapes. AlBeMet®, Materion Beryllium & Composites' trademark
for aluminum/beryllium metal matrix composites, like many industrial materials poses a health risk only if mishandled. In its
usual solid form, as well as for finished parts, and in most manufacturing operations, it is completely safe. However, breathing
very fine particles may cause a serious lung condition in a small percentage of individuals. Risk can be minimized with simple,
proven, and readily available engineering controls such as ventilation of operations producing fine dust. Information on safe
handling procedures is available from Materion Beryllium & Composites.
RESULTS AND DISCUSSION
Phase I was performed entirely at Materion Corporation’s Elmore Ohio manufacturing facility. AM162 was vibratory loaded
into a CIP bag representing one quarter of a typical 8.1in (21-cm) inside diameter polyurethane bag. The bags were sealed &
de-aired. CIP consolidation resulted in a powder compact approximately 85% of theoretical density.
Table 2. Phase I CIPd Billet Dimensions
Billet #
Radium, in (cm)
Length, in (cm)
Weight, in (Kg)
Top
Bottom
1440
3.837 (9.75)
3.721 (9.45)
27.125 (68.90)
19.6 (8.89)
1444
3.833 (9.74)
3.707 (9.41)
27.062 (68.74)
19.5 (8.85)
1445
3.818 (9.70)
3.743 (9.50)
27.140 (68.94)
19.7 (8.94
1446
3.843 (9.76)
3.743 (9.50)
27.190 (69.00)
19.8 (8.98)
Top
Composite
7.670 (19.48)
Billet
BERYLLIUM & COMPOSITES
14710 W Portage River South Rd
Elmore, OH 43416-9502
P: +1 419.862.4533 or +1 419.862.4171 Intl: +1 419.862.4127
e: [email protected]
Diameter, in (cm)
MATERION CORPORATION
www.materion.com
© Materion Corporation
Bottom
7.450 (19.48)
The CIP'd segments were assembled in an 8-in (20-cm) diameter copper can and sealed. The sealed, segmented billet was preheated at 850°F (454°C) and extruded successfully to a 2.65-in (6.7cm) diameter round; a reduction ratio of 11:1. Extrusion of the
8-in (20-cm) diameter segmented billet required a force of 2622-tons (23 MN), and resulted in an extrusion constant K of 21;
typical of solid AM162 CIP'd billet extrusion.
Figure 2 is a pictorial comparison between a solid billet and the four quarter segments extruded in Phase I.
Metallography was performed on the as-extruded cylinder. Figure 3 is a photomacrograph showing the etched cross section of
the extruded rod. After etching, the interfaces or bond lines of the four segments can be seen by the naked eye. Radiographic and
optical microscopic analysis of the bond interfaces revealed no porosity or segregation of Be or Al. Figure 4 shows the
microstructure through the center line of the cylinder.
Figure 3. Etched cross section of extrusion showing bond lines
Centerline of Extrusion
BERYLLIUM & COMPOSITES
14710 W Portage River South Rd
Elmore, OH 43416-9502
P: +1 419.862.4533 or +1 419.862.4171 Intl: +1 419.862.4127
e: [email protected]
MATERION CORPORATION
www.materion.com
© Materion Corporation
Figure 4. Microstructure of Extruded Cylinder
Centerline of Extrusion
300X
A section of the cylinder was leached in a dilute nitric acid solution to remove the copper jacket. The section was annealed at
1100°F (593°C) prior to tensile specimen removal. Tensile specimens were removed from the center where the four
segments formed a continuous longitudinal bond; a location where any segment-to-segment bond weakness would be most
evident. Longitudinal specimens were removed with the bond line parallel to, and running the length of, the long axis of the
tensile bar. Transverse radial specimens were removed from the rod. In these specimens, the bond line traversed the gauge
length. Test results from both directions indicated no substantial deviation from typical AM162 tensile properties. Table 3
summarizes the tensile results. Density measurements on a section of the as-extruded and annealed cylinder revealed a
change after anneal of <0.03%.Phase II was carried out at Materion Beryllium & Composites and the WGF facility. Using the
same AM162 powder lot and manufacturing process as Phase I, a solid, right cylindrical CIP billet, 8-in (20-cm) in diameter and
9-in (23-cm) long, was prepared for trial extrusion. The billet was preheated at 950°F (510°C) and successfully extruded at a
reduction ratio of 11:1 on Wyman-Gordon’s' 2500-ton (22-MN) press. The extrusion required a force of 2070-tons (18 MN),
which resulted in an extrusion constant K of 16.5, closely matching the predicted value for AM162 at that temperature.
The copper jacket was removed by leaching in a dilute nitric acid solution, and the rod was annealed at 1100°F (593°C) prior
to tensile specimen removal. Longitudinal and transverse tensile specimens were removed for comparison with the segmented
billet and typical AM162 extruded and annealed properties. Tensile properties of the extruded rod compared favorably with
the segmented billet in Phase I and typical extruded and annealed AM162 properties. Table 3 is a summary of mechanical
properties. The results of Phase I and II proved feasibility for extrusion of a CIP'd, segmented AM162 billet, and confirmed
extrusion process compatibility between the extruder and Materion Beryllium and Composites.
Table 3. Comparison of Extruded/Annealed Tensile Properties
Type
Orientation
UTS ksi (MPa)
0.2% YS ksi (MPa)
Elongation %
Segment
L
64.8 (447)
51.2 (353)
9.8
Segment
L
64.8 (447)
50.1 (346)
7.3
Segment
T
53.8 (371)
49.2 (339)
2.5
Segment
T
54 (372)
49.3 (340)
3.1
Solid
L
63 (434)
46.6 (321)
10.4
Solid
L
63.7 (439)
46.1 (318)
8.9
Solid
Solid
T
T
49.3 (340)
51.9 (358)
BERYLLIUM & COMPOSITES
14710 W Portage River South Rd
Elmore, OH 43416-9502
P: +1 419.862.4533 or +1 419.862.4171 Intl: +1 419.862.4127
e: [email protected]
44.4 (306)
47.8 (330)
MATERION CORPORATION
www.materion.com
© Materion Corporation
1.1
3.3
Billet Preheat Temp oF (oC)
850 (454)
850 (454)
850 (454)
850 (454)
950 (510)
950 (510)
950 (510)
950 (510)
Typical Annealed Properties
Typical
L
61.9 (426)
47.0 (323)
10.2
Typical
Typical
T
54.5 (375)
46.7 (322)
4.2
Typical
Phase III was completed at Materion Beryllium & Composites and WGF. The same CIP billet preparation method used in
Phases I and II was applied to manufacture a 27.750-in (70.5-cm) diameter billet. The four segments of the billet are shown in
Figure 5; the tooling used to CIP the segments is shown in Figure 5; the tooling used to CIP the segments is shown in Figure 6.
Table 4 summarizes dimensions of the CIPd segments.
Table 4. Phase III CIP’d Billet Dimensions
Billet #
Radius inches (cm)
Top
Length inches (cm)
Weight inches (kg) Diameter inches (cm)
Bottom
1
13.400 (34.0)
13.355 (33.92)
30.875 (78.42)
274 (124.3)
2
13.600 (34.54)
13.475 (34.23)
31.062 (78.90)
281 (127.5)
3
13.500 (34.29)
13.460 (34.200
31.000 (78.74)
279 (126.6)
4
13.500 (34.29)
13.400 (34.0)
31.00 (78.74)
278.6 (126.4)
Composite Billet
27.2 (69.1)
Fig 6. CIPing
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
The four segments were loaded into an extrusion capsule The copper canned segmented billet was sealed, pre-heated at
950°F (510°C) and successfully extruded from a 30-in (76-cm) liner to a 10-in (25-cm) round. The extrusion required a
force of 24,408-tons (215 MN), resulting in an extrusion constant K of 15.75. This agreed with the predicted force of
25,500-tons (227 MN) for AM162 extrusion at 950°F (510°C). Figure 11 shows the actual extrusion force vs. time graph.
Figure 12 shows the as-extruded cylinder.
BERYLLIUM & COMPOSITES
14710 W Portage River South Rd
Elmore, OH 43416-9502
P: +1 419.862.4533 or +1 419.862.4171 Intl: +1 419.862.4127
e: [email protected]
MATERION CORPORATION
www.materion.com
© Materion Corporation
Figure 11. Extrusion Force versus Time Plot (Wyman-Gordon Forgings (35K Ton Press load/Position/Velocity Data)
Prior to annealing, the extruded rod was leached in dilute nitric acid to remove the copper jacket. Following the anneal,
mechanical test specimens were removed from the centerline where the four segments formed a continuous longitudinal bond,
and from random areas near the outside edge of the cylinder. Room temperature tensile, compression, and fracture toughness
tests were completed; Table 5 summarizes the results. A full cross-section of the cylinder was etched in a dilute acid solution
to reveal segment bond lines visible to the naked eye as observed in the 8-in (20-cm) diameter segmented extrusion. No bond
lines were observed in the 10-in (25-cm) round. Figure 13A and 13B show transverse and longitudinal microstructures. Density
measurements before and after anneal showed a similarly small change in density, <0.02%, as measured on the segmented
extrusion in Phase I.
Figure 12. Extruded Cylinder
BERYLLIUM & COMPOSITES
14710 W Portage River South Rd
Elmore, OH 43416-9502
P: +1 419.862.4533 or +1 419.862.4171 Intl: +1 419.862.4127
e: [email protected]
MATERION CORPORATION
www.materion.com
© Materion Corporation
Direction
Location
UTS ksi (MPa)
0.2% Y
Elongation %
Long-1
Center
60.6 (418)
44 (303)
8.9
Long-2
Center
61.4 (423)
42.4 (292)
11.1
Trans-2
Center
52.6 (363)
44.7 (308)
3.3
Trans-2
Center
50.8 (350)
40,4 (279)
1.7
Long-3
180
o
60.6 (418)
43.8 (302)
7.7
Trans-3
180o
52.7 (363)
43.2 (298)
3.3
Long-4
0
o
61.4 (423)
42.4 (292)
10.3
Trans-4
0o
51.2 (353)
44.1 (304)
2.3
Fracture Toughness
Direction
Location
LT
LT
Center
Edge
17.6 (19)
17.8 (20)
TL
Center
9.0 (10)
TL
Edge
8.9 (10)
Location
Ksi in (MPa √m)
Room Temperature Compression Testing
Compression
Compression
Strength ksi (MPa)
Yield ksi (MPa)
Compression %
Expand %
Center
100.8 (695)
39.5 92727)
22.5
29.6
o
101.5 (700)
39.5 (272)
24.8
34.1
102.8 (709)
38.0 (2
28.5
39.6
Edge-0
Edge-180o
COMPLEX SHAPE EXTRUSION EFFORT
Criteria for process feasibility was successful extrusion of an Al-20wt. % (27vol. %) Be (AlBeMet® 120) tube 2-in (51-mm)
diameter with 0.187-in (4.75-mm) wall. Extrusion of non-Be containing aluminum alloy 6061 was completed first to prove
general process compatibility with Materion Beryllium & Composites’ 3000-ton (27-MN) Farrell extrusion press in Elmore,
Ohio. Successful extrusion of the aluminum alloy was followed by A1-10% Be, designated AlBeMet® 110, and finally® AlBeMet®
120. All extrusions were performed using the 127-mm (5-in) inside diameter liner. Proprietary tooling for the extrusions was
fabricated from standard die steel.
The A16061 was purchased and extruded in as-cast/homogenized condition. The fully dense AlBeMet 110 and AlBeMet® 120
extrusion billets were prepared from pre-alloyed inert-gas atomized, screened and blended powder. Table 6 is the AlBeMet®
120 chemistry.
Table 6. AlBeMet® 120 Chemistry
Be (%)
O2 (%)
22.07
0.12
BERYLLIUM & COMPOSITES
14710 W Portage River South Rd
Elmore, OH 43416-9502
P: +1 419.862.4533 or +1 419.862.4171 Intl: +1 419.862.4127
e: [email protected]
C (%)
0.024
Al
Bal
MATERION CORPORATION
www.materion.com
© Materion Corporation
Fe (ppm)
Si (ppm)
Cu (ppm)
1215
935
315
Two A16061 extrusions were required to prove process and tooling feasibility on the Elmore press. Examination of the
extrusion seam was conducted using optical macro-and microscopy along with scanning electron microscopy (SEM). Figure
14 is a macrograph of the extrusion seam area. No seam discontinuities were observed in optical microscopic or SEM
examination. Figure 15 is a 1000X magnification of a seam showing an integral Al-Be structure. No qualitative or quantitative
testing has been performed to evaluate the mechanical properties of the seams.
This project was performed at Materion Beryllium & Composites’ Research and Development lab in Cleveland, Ohio, and at
the production facility in Elmore, Ohio. Future efforts are directed at extrusion seam characterization and process feasibility
for AlBeMet® compositions with >20wt. % (27vol. %) Be.
Figure 14. Micrograph of extrusion seam
area. 22X
Figure 15. Seam area showing integral
AlBe structure 1000X
CONCLUSIONS
1) AM 162 can be extruded to a 10-in (25-cm) diameter cylinder which exhibits typical extruded and annealed mechanical
properties.
2) CIP tooling can be manufactured to produce quarter segments of a solid cylinder.
3) No substantial change in extrusion force is required to extrude a segmented billet.
4) The segments welded together during extrusion. Mechanical properties along the seams meet the typical extruded and
annealed AM162 mechanical property goals.
5) Bond lines may be seen after a heavy etch. These are innocuous with respect to properties.
6) The bond lines cannot be resolved by optical metallographic analysis.
7) Existing extrusion technology for aluminum alloys may be modified to successfully extrude a simple hollow shape from a
solid AlBeMet® 120 billet. The mechanical integrity of the resulting extrusion seams is unknown at this time.
Note: Handling Aluminum-Beryllium Metal matrix composites in solid form poses no special health risk. Like many industrial materials, berylliumcontaining materials may pose a health risk if recommended safe handling practices are not followed. Inhalation of airborne beryllium may cause a
serious lung disorder in susceptible individuals.
The Occupational Safety and Health Administration (OSHA) has set mandatory limits on occupational respiratory exposures. Read and follow the
guidance in the Material Safety Data Sheet (MSDS) before working with this material. For additional information on safe handling practices or
technical data on Aluminum Beryllium Metal matrix composites, contact Materion Beryllium & Composites.
MAAB-010-0
BERYLLIUM & COMPOSITES
14710 W Portage River South Rd
Elmore, OH 43416-9502
P: +1 419.862.4533 or +1 419.862.4171 Intl: +1 419.862.4127
e: [email protected]
MATERION CORPORATION
www.materion.com
© Materion Corporation