THE SIMILARITY LAW BETWEEN THE TEMPERATURE DEPENDENCES OF YIELD STRESS AND MICROYIELD STRESS EVALUATED FROM INTERNAL-FRICTION

The amplitude-dependent internal friction gives the temperature dependence of the microyield stress sigma(epsilon)(T) at a very low (of the order of 10(-10)-10(-8)) value of the reversible dislocation strain. A similarity law tie. a proportionality of the macro- and microyield stresses) has been found for a,(Tf but not for other measures of microyield. The similarity law is not consistent with the conventional thermally activated approach. An approach based on the temperature dependence of the stress-induced plasticity is concluded to be responsible for the temperature dependences of both micro- and macroyield stresses.