Simultaneously enhanced strength and plasticity of laser powder bed fused tantalum by hot isostatic pressing

The effects of hot isostatic pressure (HIP) treatment (850 °C/1350 °C, 150 MPa, 4 h) on the microstructure and mechanical properties of laser powder bed fused tantalum were investigated. The results show that the heat treatment process with high pressure and low temperature (relative to the melting point) limited the growth of tantalum grain size and homogenized the microstructure. The hot isostatic pressure of 850 °C/1350 °C and high pressure of 150 MPa promote plastic deformation in the pore region of the laser powder bed fused tantalum and reduce the pore size, thus increasing the sample densities to more than 99 %. After 1350-HIP, all the properties of laser powder bed fused tantalum are significantly improved, and the hardness, ultimate tensile strength, and elongation of tantalum are further improved to 273 HV (40.72 %), 551 MPa (16.24 %), and 43.4 % (18.26 %).