Effect of hot isostatic pressing treatment on porosity reduction and mechanical properties enhancement of 316L stainless steel fabricated by binder jetting

Abstract

In this work, a hot isostatic pressing (HIP) treatment was used to reduce the pores and improve the mechanical properties of binder jetting (BJ) fabricated 316L stainless steel. The relative density of the HIP treated samples sintered under vacuum, nitrogen, and argon atmospheres increased from 89.20∼90.76% to 94.02∼98.35%. The mean diameter of the internal closed pores decreased from 11.83∼14.70 μm to 0.94∼1.53 μm, and the internal porosity reduced from 5.47∼8.67% to 0.14∼0.35%. A remarkable enhancement of mechanical properties was achieved with the tensile strength by ∼15% and the elongation by ∼100% due to the reduction of porosity. The mechanical properties of the BJ 316L sintered under nitrogen and treated with HIP were even better than those of the direct powder HIP components due to the interstitial solution strengthening. These findings will be a valuable reference for optimising the HIP parameters to produce metal BJ components with superior mechanical properties.