Abstract
With the advancement of individual medicine, the additive manufacturing of NiTi alloys, which are used as biomedical implantation materials, is becoming increasingly popular. However, the insufficient corrosion resistance of these alloys still requires improvement. In this study, we fabricated various NiTi alloys with and without TiC addition using selective laser melting (SLM). The effects of TiC addition and content on the microstructure, phase transition, and corrosion resistance of SLM-fabricated NiTi alloys were thoroughly investigated. The results indicated that TiC addition promoted grain and microstructure refinement and induced a transition from columnar to equiaxed grains. In addition, the formation of martensite in NiTi was suppressed, which could be attributed to the synergistic action of grain refinement and second phase dispersion toughening of TiC grains. Furthermore, because of the formation of a thicker protective passive layer with TiC addition, the corrosion resistance of the SLM-fabricated NiTi alloys was obviously improved. This study illustrated TiC addition as an effective method for enhancing the performance of SLM-fabricated NiTi alloys.
