The plastic flow model in the healing process of internal microcracks in pre-deformed TC4 sheet by pulse current

Abstract

In this paper, the distribution of microcracks in titanium alloys (TC4) before and after electropulsing treatment (EPT) was observed by X-ray microscopy (XRM). The results show that EPT has obvious healing effect on internal microcracks in the TC4 tensile specimen. Based on Mises yield criterion and the results of finite element analysis in the internal microcrack healing process in titanium alloy, the elastic-plastic deformation characteristics during microcrack healing were analyzed. The results show that the plastic deformation around the microcrack is nonuniform due to the uneven distribution of temperature and thermal compressive stress during EPT. The region with large plastic deformation looks like a thick-walled ellipsoid-shaped ring surrounding the microcrack, where the elongation of the material along the normal direction of the microcrack surface is the main cause of the microcrack closure. The deformation ring plastic flow model was proposed to explain the microcrack closure mechanism by pulse current.