In-situ SEM-EBSD tensile study at room temperature of additive manufactured TA15 alloy: Microstructure, texture and mechanical behavior

TA15 alloy, widely utilized in the aerospace industry for its exceptional mechanical properties, was examined in this study for its anisotropic microstructure evolution and deformation behavior in laser melting deposition (LMD)-fabricated samples at room temperature. Specimens were extracted from build (Z-) and scanning (X-) directions and their microstructures and mechanical properties were compared. A method based on in-situ electron back scattered diffraction (EBSD) tensile testing , was used by inserting a tensile stage into scanning electron microscopy (SEM) to observe the real-time microstructure evolution with the change of dynamic tensile force . The evolution of slip bands, grain rotation, grain-to-grain misorientation, and the dynamic change of mechanical properties were also systematically investigated. The results demonstrated that the anisotropic mechanical properties along the Z- and X-directions in LMD-fabricated TA15 alloy stemmed from variations in microstructural anisotropy. Z-direction specimen exhibits high elongation and reduction of cross section , whereas, high tensile strength and yield strength were identified in X-direction. Furthermore, the texture behavior, crack propagation and fracture mechanism are discussed for each specimen orientation.