Fretting fatigue behaviours of SiC reinforced aluminium alloy matrix composite and its monolithic alloy

Abstract

This study presents the experimental and FEA (finite element analysis) investigations on the fretting fatigue behaviours of the metal matrix composite, 2124 Al–Cu–Mg alloy reinforced with 17 vol% of 3 μm SiC particles by a powder metallurgical route and its equivalent monolithic alloy, 2024. The predicted stress concentration and orientation from the nonlinear FEA stress analyses are aligned with the experimental observation including fretting wear damage and crack initiation and propagation. Compared with its equivalent monolithic alloy, the composite in the naturally aged condition (T4) demonstrates similar subsurface degradation but the crack propagation life is much shorter. In general, the composite has shown superior fretting fatigue performance in the low cycle regime (104 to 4x105 cycles) but not in the high cycle regime (4x105 to 107 cycles). Its fretting fatigue behaviour is interpreted in terms of higher wear resistance, delayed crack initiation, superior tensile strength in the low cycle regime. The reported fretting fatigue performance of the composite suggest the different material behaviours in low and high cycle regimes should be considered when developing a fretting fatigue damage model and assessing an engineering design.