Effect of hot isostatic pressing and post-processing thermal treatments on the mechanical properties of C-18150 copper alloy fabricated by laser powder bed fusion

Abstract

C-18150 is a precipitation hardening copper alloy that has increasingly gained interest in additive manufacturing (AM) for applications in space, aerospace, electronics and automotive due to its excellent combination of electrical and thermal conductivity, thermal softening resistance at elevated temperatures, moderate strength, and high ductility. In this work, the effect of post-processing thermal treatments on the tensile properties of C-18150, fabricated by laser powder-bed-fusion (L-PBF), using high productivity printing parameters, was investigated. For this purpose, the reference as built and aged (480°C, 5 h) samples were compared with those of post-processed, prior to final ageing, under different conditions: (i) solution annealing (980 °C, 3 h), (ii) hot isostatic pressing (HIP) (950 °C, 150 MPa), followed by solution annealing, and (iii) HIP (980 °C, 150 MPa) followed by uniform rapid quenching aimed at eliminating the solution annealing step. Tensile behaviour was discussed in view of microstructural evolution and defects (e.g. porosity) in relation to the post-processing thermal treatments.