Enhanced corrosion behavior of selective laser melting S136 mould steel reinforced with nano-TiB2.

• Nano-TiB 2 reinforced S136 mould steel composites were fabricated by SLM. • Effects of TiB 2 on microstructures and corrosion property of composites were studied. • The SLM composites possessed finer grains compared to the SLM pure S136. • Higher electrochemical property and less weight loss was obtained for SLM composites. The S136 mould steel matrix with varying mass fractions of TiB 2 (0–2.5 wt%) were produced by selective laser melting (SLM). This study mainly focused on the influence of TiB 2 content on the microstructure and corrosion property of the S136 composites in detail. The electrochemical method and weight loss test in the 3.5 wt% NaCl solution and 6 wt% FeCl 3 solution were conducted to determine the corrosion resistance of the composites. Results demonstrated that the SLM 0.5 wt% TiB 2 /S136 composites possesses higher corrosion and pitting potentials as well as lower corrosion current density and weight loss compared to that of other samples owing to the existence of the finer grains and TiO 2 passive film. Furthermore, the corrosion property of the composites decreased with the gradually increasing TiB 2 content associating with more defects and galvanic cells, which was detrimental to the corrosion property. Herein, the corrosion mechanism of the SLM TiB 2 /S136 composites was also deeply discussed in this paper. [ABSTRACT FROM AUTHOR]