Rapid fabrication of bulk-form TiB2/316L stainless steel nanocomposites with novel reinforcement architecture and improved performance by selective laser melting

Selective laser melting (SLM), a novel additive manufacturing technology, was employed to fabricate nanostructured TiB2/316L stainless steel nanocomposites with varying nanoscale TiB2 content (vol.%). The resulting microstructure of the SLM-processed nanocomposites was characterized by SEM, EBSD, and TEM, while the mechanical properties were characterized using microhardness, compression tests, and wear tests. It was found that the microstructure and mechanical properties of the SLM-processed nanocomposites were sensitive to the TiB2 content. The optimal TiB2 content was determined to be 10 vol.%. Further, the TiB2 particles were homogeneously dispersed and they formed nanoscale ring-like structures along the grain boundaries. In contrast to the SLM-processed unreinforced 316L stainless steel sample, the TiB2/316L nanocomposites exhibited higher microhardnesses and yield strengths while showing low coefficients of friction and wear rates; this was owing to the combined effects of grain refinement and grain-boundary strengthening. The nanocomposites showed good combination of compression yield strength and ductility during microcompression tests. (C) 2016 Elsevier B.V. All rights reserved.