The tensile and tensile-creep deformation behavior of Ti–8Al–1Mo–1V(wt%)

Abstract

The deformation behavior of titanium (Ti) can be complex due to the lower crystal symmetry of the hexagonal α phase compared with metals based on cubic phases. The tensile and tensile-creep deformation behavior of a Ti–8Al–1Mo–1V(wt%) alloy with a weak crystallographic texture was investigated in-situ straining scanning electron microscopy. Tensile experiments were performed at room temperature (RT), 260°C, 455°C, and 650°C, while tensile-creep experiments were performed at 370°C and 455°C. Electron backscattered diffraction (EBSD) was performed both before and after the deformation, and slip trace analysis was used to identify the activation of the slip modes as a function of temperature and the associated global-stress-state Schmid factors. While extensive slip was characterized during the tensile tests, no twinning was observed. During the RT tensile tests the majority of the slip observed was on prismatic planes, while the relative activity of basal slip increased with temperature, such that at 455°C, basal slip and prismatic slip were equally active. Some grain boundary and triple point cracking occurred during the elevated-temperature tensile deformation, while less slip activity and more grain boundary ledge formation were observed during the tensile-creep deformation. During tensile-creep, basal slip was more prevalent than prismatic slip and some transgranular cracks formed.