The influence of internal stresses on the fracture toughness of α/β titanium alloys

Abstract

The influence of internal stresses on fracture toughness was investigated in α/β titanium alloys. It was shown that the direct linkage of K IC to various microstructural parameters was not so conclusive, since the different parameters act simultaneously on fracture toughness. On the contrary, the metallurgical parameters change the plastic strain incompatibilities inside the material. Thus X, which is a macroscopic measurement of these incompatibilities, is the relevant parameter to account for the different metallurgical influences on toughness. The influence on X of the α-phase percentage, aspect ratio, and the secondary α-phase percentage was determined, and it was established that low internal stresses could provide high fracture toughness. The present work also showed the ability of a modified Gurson-Tvergaard (GT) model to calculate the experimental K IC value.