Mesoscopic Features of Plastic Strain in Step Yield.

Krishtal, M. M.

A specially developed method for isolating the macroscopically homogeneous part of plastic strain in step yield (SY) of materials is used for analyzing stress-strain curves of alloy AMg5 obtained at various strain rates in the range of appearance of SY. It is shown that the beginning of the SY corresponds to the inflection point in the linear dependence of the true stresses (S) on the true plastic strain (e) in S – e1/2 coordinates, which is identified as the appearance of a new individual strain stage caused by the change in the strain mechanism at the mesolevel. The established change in the strain mechanism is shown to consist in an abrupt growth of the elementary volume of plastic strain due to the appearance of a space-time correlation in the development of the strain microprocesses, which is responsible for macrolocalization and general loss of the stability of the strain. The developed experimental and computational method is used to determine the rate sensitivity of the strain resistance to step yield, which is a positive quantity that increases with the strain.

MESOSCOPIC phenomena (Physics); STRAINS & stresses (Mechanics); ALLOYS; LINEAR dependence (Mathematics); PLASTIC analysis (Engineering); STRESS-strain curves

Metal Science & Heat Treatment, 2002, Vol 44, Issue 9/10, p393

0026-0673

Academic Journal

10.1023/A:1021955201466