Tungsten particle-reinforced 316L steel fabricated by laser melting deposition: Microstructure and mechanical properties

Abstract

316L steel manufactured by laser melting deposition (LMD) has extensive uses in industry. Nevertheless, relatively low wear resistance and tensile strength limit its engineering applications. In this study, tungsten (W) because of high hardness and strength properties is used as a reinforcing phase to improve these weaknesses of 316L steel. To assess comprehensively the impact of W content on 316L steel, 316L/W composite coatings with different W contents (8 wt%, 16 wt% and 24 wt%) were prepared by LMD. The microstructure and phase composition were characterized utilizing scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffractometry (XRD), respectively. The addition of W particles accelerates the cooling and solidification rate of the molten pool and hinders the growth of dendrites, thereby refining the grains. In addition, the microhardness, wear and mechanical tensile properties were also studied. The findings show that the microhardness gradually increases as the addition of W content. Meanwhile, the yield strength (YS) and ultimate tensile strength (UTS) are also improved, but this is accompanied by the sacrifice of elongation. When the W content is 16 wt%, the composite coating has the optimal wear resistance, and the wear rate is reduced to 6.11 % of the 316L alloy coating.