Hybrid Processing of AZ91 Magnesium Alloy/Nano-Al2O3 Composites

Abstract

In the present work mechanical and wear behaviour of AZ91 magnesium alloy based composites, reinforced with nanoAl2O3 particles is studied. The composites with different amount of alumina particles are fabricated by a hybrid processing approach. The hybrid processing involved alumina particles dispersion in molten AZ91 alloy by mechanical stirring assisted with ultrasonic processing. Dry sliding wear tests are performed using a pin on disc apparatus against hardened steel at loads ranging from 4.9 N to 14.7 N. The microstructural investigation revealed that, a refined microstructure is obtained because of the heterogeneous nucleation induced by ultrasonic processing and nanoAl2O3 dispersion. Hardness, yield strength and maximum compressive stress of the nanocomposites are found to be superior to that of the matrix alloy. The resistance against wear is increased due to incorporation of reinforced nanoAl2O3particles. The wear rate of nanocomposite is decreased with increasing the amount of the reinforcement. The identified wear mechanisms are abrasion and oxidation.