Publication

Abstract : Aluminium and its alloys have a wide range of applications, especially in the automotive sector. Typically, aluminum alloys are utilized in pistons and cylinders of automotive engines. Hence, repeated sliding with low amplitude (fretting) under adverse thermal and mechanical loading conditions dominates the wear of components. In this present work, the effect of solutionizing time on the fretting wear behaviour of Al-Si-Mg-Ni hypoeutectic alloy against alumina ball is investigated under varying normal loads of 5, 10, and 15 N. The fretting wear characteristics in terms of friction coefficient, wear volume and wear scar analyses with the aid of scanning electron microscope and optical profilometry have been systematically conducted. Results showed that with varying solutionizing time, a considerable change in the microstructural aspects of Al-Si-Mg-Ni alloy in the form of Al3Ni and Si precipitation is observed. Moreover, a refinement in the grains is also noticed as the solutionizing time increased from 2 to 10 h. The improved wear resistance is corroborated by the increased hardness arising from the improved intragranular precipitation of Al3Ni and Si. In addition, a reduction in the steady-state coefficient of friction with an increase in the normal load and a concomitant decrease in the wear scar size is also reported. This friction coefficient reduction could be ascribed to the presence of a tribolayer generated between the contacting surfaces for which the formation and coverage are escalated with increasing normal loads.