Influence of CeO2 reinforcement on microstructure, mechanical and wear behaviour of AA2219 squeeze cast composites

Abstract

The present investigation deals with development of AA2219 composites with different weight fractions of Cerium oxide (CeO2) reinforcement and characterizing the microstructure and mechanical properties thereof. XRD and SEM micrograph confirm the presence of CeO2 particles and Al2Cu precipitate. The grain size of 0, 0.5, 1.0, 1.5 and 2 wt% CeO2 composites are 483, 453, 411, 362 and 328 μm, respectively. Addition of CeO2 significantly reduces the dendritic morphology and refines the α-Al grain structure. 2 wt% CeO2 addition has yielded the maximum hardness of 124 HV and yield strength of 87 MPa in all the composites developed. Additionally, the developed composites were evaluated by examining the wear characteristics with the co-efficient of friction (COF) and the specific wear rate. In this study, Taguchi's L25 orthogonal array was used to optimize the parameters like reinforcement fraction, load and sliding distance. Signal-to-noise ratio (S/N ratio) and analysis of variance (ANOVA) are used to obtain the parameters highly influencing the wear behaviour. Adhesive wear is exhibited by ploughing at lower loads and delamination is observed with increasing load. Deep shallow ploughs with embarked abrasion are observed at higher loads.