PLASTIC-FLOW AND FRACTURE IN PD80SI20 NEAR TG

Above about 0.7Tg, plastic flow in Pd80Si20 becomes homogeneous in the normal ranges of strain rate of short term laboratory experiments. In this range samples exhibit considerable anelasticity before general yield. Load maxima are observed simultaneously with general yield and are followed soon after by a classical behavior of slanted necking, and a mixture of rupture and fracture accompanied by elongations of about 3% typical of a non-hardening rupturing solid of the given thickness and gauge length. This relatively stable behavior has permitted measurement of the stress exponents m of the strain rate for the material at flow at these temperatures. These exponents decrease to unity as the test temperature approaches Tg. The temperature dependence of the flow stress and its strain rate dependence are in good accord with Argon's recent theory for plastic flow in metallic glasses. © 1979.