Characterizations of Temperature-Dependent Tensile Deformation and Fracture Features of Commercially Pure Titanium

Abstract

Tensile deformation and fracture behavior of a commercially pure (CP) titanium were investigated at different temperatures through mechanical tests, microstructural observations and fractal analyses. It was found that, with increasing temperature, the number and size of microvoids formed along shear bands (SBs) or at the intersections of SBs on the deformed specimen surface increase, and the fractal dimensions of the scanning profile at the surface near fracture increase correspondingly, and the ones measured perpendicular to the tensile direction is obviously larger than those parallel to the tensile direction, indicating an increased concentration of plastic deformation of CP Ti along the tensile axis. The diameter and depth of dimples on the fracture surfaces of CP Ti increase significantly with increasing temperature, giving rise to a higher fracture surface roughness reflected by a higher fractal dimension. TEM observations demonstrated that the plastic deformation of CP Ti is gradually occupied by dislocation slipping rather than twinning with increasing temperature. This is in good agreement with the fractal analyses of the deformation and fracture features.