SUPERPLASTIC DEFORMATION BEHAVIOR OF SUPERHARD Al ALLOY LC4

The superplasticity of high strength superhard A1 alloy LC4 was improved to a great extentby modified thermomechanical treatment.Its maximum elongation may be up to 2100% un-der deformation at initial strain rate of 8.33×10~(-4) S~(-1) at 510℃.Observations of themicrostructure changes revealed that with the increase of the deformation,the grain grows andthe alloy exhibits strain hardening.The excellent elongation of the alloy seems due to the in-crease of grain stability under deformation.