Manufacturing, Microstructure, Room and High Temperature Mechanical Properties of Pure Tantalum Manufactured by Cold Spray Additive Manufacturing

Pure Ta, a high melting point refractory metal, was fabricated by cold spray additive manufacturing (CSAM) and the mechanical properties at various temperatures from room temperature to 950°C was investigated. CS Ta shows that irregular shaped initial powder elongated in a direction perpendicular to the spraying direction. In addition, microstructural evolution was occurred in the process of accommodating harsher plastic deformation along the powder boundaries. A compression test confirmed that room temperature yield strength was approximately 901 MPa, which is four to six times higher than pure Ta produced using conventional processes such as vacuum arc melting etc. Also, CS Ta showed excellent mechanical properties even at high temperatures, and such properties were confirmed to be retained up to approximately 950°C. Surface and microstructural observations after deformation confirmed that the sample crumbled in a compression test at 800°C. However, the sample’s shape was retained in temperatures above 800°C. Such a phenomenon was caused by interaction between high temperature oxidation behavior and microstructure evolution. Based on such findings, the relationship among the microstructure, room to high temperature deformation behaviors of CS Ta were also discussed in this study.