Nanopowder derived Al/h-BN composites with high strength and

Al/h-BN composites with high tensile and compressive strength at room and elevated temperatures, as well as enhanced ductility, were obtained by a combination of ball milling (BM) and spark plasma sintering (SPS) using Al and hexagonal BN nanopowders (0, 1, 2, 3, 4, 5, and 10 wt% of h-BN). The use of two types of nanopowders is intended to ensure uniform distribution of the reinforcing phase and improve Al-BN chemical interaction at the manufacturing stages by increasing the surface-to-volume ratio. Due to Al with h-BN interaction, the Al/h-BN composites were simultaneously strengthened by three types of nanoparticles: Al2O3, AlN(O) and h-BN, predominantly located along the Al grain boundaries. Compared to BM +SPS aluminum, the tensile strength of Al-2 wt%BN composite increased by 82% (25 degrees C), 64% (300 degrees C), and 65% (500 degrees C), and the compressive strength by 107-119% (25-500 degrees C) while maintaining high elongation to failure in tension (13.6%, 11.6% and 10.8%) and compression (12.6%, 13.1% and 8.1%) at 25 degrees C, 300 degrees C, and 500 degrees C, respectively. In terms of combination of tensile and compressive strength at room and elevated temperatures, the Al/h-BN materials are superior to many other Al-based composites. The high strength and relative elongation to fracture of the Al/h-BN composites can be explained by the formation of a heterogeneous microstructure consisting of pure Al grains surrounded by a metal-matrix composite material with fine metal grains and reinforcing ceramic nanoinclusions. The obtained results significantly expand the scope of Al/h-BN materials, since their strength at 500 degrees C is higher than that of pure Al at room temperature. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

Al/h-BN composites with high strength and ductility were successfully obtained through ball milling and spark plasma sintering. The composites showed improved tensile and compressive properties at room and elevated temperatures. The combination of Al and h-BN nanoparticles resulted in enhanced strength and elongation to fracture, making the materials superior to other Al-based composites.