Stress-Strain Behavior of Ti-Nb Alloys under Compressions along Linear Strain Paths and Bilinear Plane Strain Path

摘要

Titanium alloys containing beta stabilizing elements exhibit several superior properties compared to other conventional metals. However, there are unknowns about the mechanical behavior of titanium alloys under biaxial compressive stress conditions. In this study, uniaxial compression and biaxial compressions along linear strain paths and bilinear strain path were performed on titanium-niobium alloys (Ti-Nb alloys) in order to investigate the influence of Nb contents on the compressive deformation behaviors. The results of compressions along linear strain paths revealed that the flow stress decreased while the ductility increased with the increase of the Nb content. It was found that the phenomenon was mainly due to changes of the microstructure and the primary plastic deformation mechanism. Those changes also induce anisotropic hardening. Based on those results, quantitative expression of the stress-strain relation with taking into account the Nb contents was discussed. The investigation on the effect of strain path change on the flow stress revealed the niobium dependency of the stress-strain response before and after the abrupt strain path change.