Tribological behavior of boron nitride nanoplatelet reinforced Ni3Al intermetallic matrix composite fabricated by selective laser melting

Recent advances and demands in high-temperature structural materials drive a large amount of research to Ni3Al intermetallic composites. In this research, hexagonal boron nitride nanoplatelet (BNNP) reinforced Ni3Al composites were successfully fabricated by selective laser melting (SLM), in which in-situ formed Ni3Al columnar grains preferentially develop along their < 100 > direction being parallel to the build direction, and these added BNNPs distribute homogeneously in Ni3Al matrix. Synergetic strengthening and toughening mechanisms associated with the added BNNPs, such as increased dislocation density, Orowan mechanism, BNNP pull-out and BNNP bridging, play significant roles in the improved mechanical properties of Ni3Al composite. The BNNP/Ni3Al composite exhibits excellent anti-friction (similar to 0.22-0.26 of coefficient of friction) and anti-wear resistance (similar to 0.9-2.1 x 10(-5) mm(3) N-1 m(-1) of wear rate), decreasing by up to similar to 24% and similar to 51.2%, respectively, as compared to those of SLMed Ni3Al sample. (C) 2019 The Authors. Published by Elsevier Ltd.