Effect of friction stir processing on the wear rate of as-cast AZ91D Magnesium alloy

Magnesium (Mg) alloys known to have the lowest density amongst other engineering materials used for structural applications. They are emerging as a promising material, particularly in automotive and aerospace industry. But the poor wear characteristics of Mg alloys restrict their use in many applications. In the present investigation, friction stir processing (FSP) of as-cast AZ91D Mg alloy was performed with the objective to improve its wear properties. The FSP was carried out at a tool rotation speed (TRS) of 600, 900 and 1200 rpm. The tool travel speed was kept constant at 70 mm/min. A pin-on-disc tribometer was used to perform dry sliding wear experiments at an optimized set of parameters. FSPed specimens demonstrate a substantial grain refinement and decomposition of coarse beta-Mg17Al12 particles into Mg matrix. At a TRS of 600 rpm, the average grain size was reduced to 25 lm and the microhardness was increased to 81 Hv. The refined microstructure and improved hardness are expected to have provided better wear resistance in FSPed samples. (C) 2021 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Technological Advancements in Materials Science and Manufacturing.