Microstructure Formation Driven by Stored Energy and Mechanical Property of Pure Titanium Recycled from Chips by Severe Plastic Deformation

Abstract

It is of practical significance to improve the recycling value of hard-to-deform titanium wastes by means of melting-free technologies. One such technology, severe plastic deformation in the form of equal channel angular pressing (ECAP) was used to consolidate chips of commercial purity titanium. Electron backscatter diffraction (EBSD) was used to resolve the microstructure into high angle grain boundaries (HAGBs, with misorientation ²15°) and low angle grain boundaries (LAGBs, <15°). The strain energy stored in HAGBs and LAGBs were considered to be the primary driving force of dynamic recovery (DRV) and dynamic recrystallization (DRX). As a result of DRV and DRX, the formation of microstructure was analyzed by evaluating the stored energy for various ECAP conditions. The ductility of the recycled titanium was analyzed by verifying the failure mode according to the inspection of the fracture surface of the tensioned specimen with scanning electron microscopy.