Question

What is the ductility of age-hardened Al-4.5%Cu alloy?

(a) 15%

(b) 20%

(c) 40%

(d) 55%

I have been asked this question in final exam.

My question is from Metal Spraying and Hard Facing, Age Hardening in division Wear of Metals, Mechanical Properties and Testing of Engineering Material & Metallurgy

Answer 1

Right choice is (b) 20%

For explanation I would say: Al-4.5%Cu is an example of an age-hardened alloy. At the age hardened stage, it achieves as ductility of 20% with a tensile strength of 4225 kg/cm2. As it overages, the ductility drops to 20%.