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A superplastic Al-Li-Cu-Mg-Zr powder alloy with high hardness and modulus

Journal Article · · Metallography; (United States)

Structure/property studies were made on an experimental Al-3.18% Li-4.29% Cu-1.17% Mg-0.18% Zr powder alloy, which is of the low density/high modulus type. Alloy powder was made by the P and W/GPD rapid solidification rate (RSR) process, canned, and extruded to bar. The density was 2.458 x 10/sup 6/ g/m/sup 3/. The material was solution-treated, and aged at 149/sup 0/C(300/sup 0/F), 171/sup 0/C(340/sup 0/F), and 193/sup 0/C(380/sup 0/F), using hardness tests to determine the aging curves. Testpieces solution-treated at 516/sup 0/C(961/sup 0/F) showed an average yield strength (0.2% offset) of 43.3 ksi (299 MPa) and ultimate tensile strength of 50.0 ksi (345 MPa), with 1% elongation, which increased to 73.0 ksi (503 MPa) and 73.1 ksi (504 MPa), respectively, with only 0.2% elongation, on peak aging at 193/sup 0/C(380/sup 0/F), with a modulus of elasticity of 11.4 x 10/sup 6/ psi (78.3 GPa). Hardness values reached 90-92 R/sub B/ on aging at 149-193/sup 0/C(300-380/sup 0/F). The as-extruded alloy showed superplastic behavior at 400-500/sup 0/C(752-932/sup 0/F) with elongations of 80-185% on 25.6 mm, peaking at 450/sup 0/C(842/sup 0/F). An RSR Al-2.53% Li-2.82% Mn-0.02% Zr extruded allow showed only 18-23% elongation at 400-500/sup 0/C(752-932/sup 0/F).

Research Organization:
Materials Technology Dept., United Technologies Research Center, East Hartford, CT 06108
OSTI ID:
5284676
Journal Information:
Metallography; (United States), Journal Name: Metallography; (United States) Vol. 19:3; ISSN MEIJA
Country of Publication:
United States
Language:
English