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The Effect of Fe-Addition to Al-10Ti Alloy on Superplasticity at High-Strain Rates

Published online by Cambridge University Press:  10 February 2011

D. Kum
Affiliation:
Korea Institute of Science and Technology, P.O. Box 131, Seoul 130-650, KOREA, [email protected]
W. J. Kim
Affiliation:
Hong-ik University, 72-1 Mapo-ku, Sangsu-dong, Seoul 121-791, KOREA
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Abstract

Ultra-fine microstructure consisting of equiaxed Al-grains and aluminide particulate was produced by powder metallurgy process using gas-atomized powders of Al-10wt%Ti-2wt%Fe alloy. High strain rate superplasticity (HSRS) has been investigated at 873-923K and strain rates higher than 10−3s−1 in tension, and total elongation up to 500% was observed at the strain-rate of 10−1s−1. The strain rate vs. flow stress behavior exhibits the typical aspect of HSRS such as the increase of strain-rate sensitivity exponent with increase in strain-rate and an apparent activation energy higher than that for lattice diffusion in aluminum. The concept of threshold stress has been incorporated to illustrate the HSRS behavior, where the stress exponent of 3 describes the experimental data. The determined threshold stress showed strong temperature dependency as in the case of a similarly processed Al-10wt%Ti alloy, which exhibited the stress exponent of 2 in the same testing conditions. Solute drag mechanism has been postulated for the Al-Ti-Fe alloy.

Type
Research Article
Copyright
Copyright © Materials Research Society 2000

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