Tribological investigations on h-BN/NiTi inoculated Al7075 composite developed via ultrasonic aided squeeze casting

Achieving superior tribological resistance in 7xxx series composite remains a formidable challenge due to the improper selection of reinforcements. In the present study, highly wear resistant h-BN/NiTi reinforced Al7075 composite was successfully fabricated by ultrasonic aided squeeze casting technique. Prior to wear studies crystallographic orientation, texture, residual stress, grain size and its misorientation angle were analysed using Electron Backscattered Diffraction (EBSD). It has been found that addition of heterogenous nuclei Ti had improved the wettability of Al and promoted grain refinement. In addition, high squeeze casting pressure of 400 MPa resulted in development of high compressive residual stresses as indicated by Kernel Average Misorientation (KAM) map. Due to the combined effect of reinforcement addition and high compressive residual stresses easy sliding was facilitated by lamellar lubrication mechanism. As a result, the counterpart had shown superior wear resistance by exhibiting low friction coefficient of 0.2. (c) 2020 Elsevier B.V. All rights reserved.