Effect of R-Curve and Inhomogeneities on the Toughness Measurement of Metallic Glasses

Abstract

ABSTRACTSub-critical crack growth is a function of the degree of relaxation of the amorphous structure and has implications regarding the measurement of annealing embrittlement and the dependence of embrittlement on temperature. The variation of Kc with annealing time is strongly dependent on the size of the initial crack length. Quenched-in inhomogeneities seem to be always present. Their effect depends on the specific testing conditions, especially the testing temperature because the ductile-brittle transition is a function of the degree of relaxation of the amorphous structure. Some doubt is also cast on the accepted assumption that a chevron pattern is representative of plane strain crack propagation conditions.