Development of Wear Mechanism Map for Al–4Mg Alloy/MgAl2O4 In Situ Composites

Abstract

Dry sliding wear behaviour of Al–4Mg alloy and Al–4Mg alloy/MgAl2O4 in situ composites was examined under normal loads of 10–30 N at sliding speeds of 1, 3, 5 and 7 m/s and sliding distance of 1500 m using a pin-on-disc apparatus. Al–4Mg alloy with different wt% (1, 2 and 3) of MgAl2O4 in situ composites was synthesized via ultrasonic cavitation by the addition of H3BO3 powders. Unreinforced alloy and composites were characterized to conclude the role of MgAl2O4 in modifying the wear behaviour of the composite. Worn-out samples and wear debris were examined by scanning electron microscopy and X-ray diffraction in order to obtain the major wear mechanisms of the developed composites. The addition of MgAl2O4 significantly reduces the wear rate of Al–4Mg alloy at higher loads. The operating wear mechanisms observed were delamination, oxidation, abrasion, adhesive, thermal softening and plastic deformation modes.