An investigation into yield surfaces and plastic flow laws for f.c.c. metals at room temperature and a low temperature (T = 78°K)

Experimental investigations are made into yield criteria and stress-strain relationships for aluminium and copper at room temperature and 78°K by tension-torsion testing of tubular specimens. Initial and subsequent yield surfaces are determined after prestrain in tension and torsion.The laws of normality and convexity and the possibility of the existence of corners on the yield surfaces are considered.