Microstructural and texture evolution investigation of laser melting deposited TA15 alloy at 500°C using in-situ EBSD tensile test

Abstract

The deformation behavior in polycrystalline Laser melting deposited (LMD) TA15 alloy was investigated at a temperature of 500°C using advanced in-situ Secondary electron microscopy (SEM) tensile setup coupled with Electron backscatter diffraction (EBSD). The grains morphology, crystal orientation, preferred pole texture, activated slip traces, grain boundaries evolution, and strain-induced misorientation were systematically analyzed during tensile straining. It was determined that the diverse α-grains (crystal orientation and morphology) revealed inhomogeneous deformation under tensile loading. The overall strain was allocated by grain rotation and substructure formation. The preferred oriented (0001) pole texture maximum was increased during initial strain level. In contrast, at higher strain, the texture intensity was decreased due to the formation and relocation of the newly formed substructures. The fraction of low angle grain boundaries (LAGBs 2–10°) was increased continually with increasing strain. Strain-induced dislocations within larger grains formed new LAGBs, and the increasing fraction of LAGBs was validated by Kernel average misorientation (KAM) map. The prismatic slip mode was identified as the primary active slip system at the initial deformation stage. The fraction of basal and pyramidal <a> slips increased as the strain increased, describing the opposite trend to prismatic slip. The grains rotation and strain accumulation at the grain boundaries accommodated the plastic deformation, ultimately causing boundary sliding.