WEAR BEHAVIOUR OF HEAT-TREATED ZA27/SIC/TIB₂ HYBRID COMPOSITE: A DECISION MAKING APPROACH USING TAGUCHI DESIGN AND ANOVA

Abstract

This study presents a methodology for examining the effects of aging temperature and wear parameters on the wear behavior of a ZA27/SiC/TiB₂ hybrid composite. The ZA27 alloy is widely used in applications requiring high bearing strength and wear resistance but suffers performance degradation at temperatures above 100°C. The addition of SiC and TiB₂ helps overcome these limitations. To address this research gap, a hybrid composite was developed using ZA27 alloy as the matrix (85 wt.%), reinforced with equal proportions of SiC and TiB₂ (15 wt.%). The composite was fabricated via mechanical stir casting to ensure uniform particle dispersion. Solution treatment at 360°C was performed for 5hours to obtain a homogeneous solid solution, followed by aging at different temperatures to facilitate precipitation hardening. A Taguchi L9 orthogonal array was used to design the experiments, varying sliding speed, normal load, and aging temperature. ANOVA results revealed that normal load had the most significant effect on wear and friction(COF), while aging temperature had a moderate influence on wear behaviour. The hardness of the optimally aged sample is 128.5, whereas the base alloy exhibits a hardness of 102.2, indicating a significant improvement due to aging. At a normal load of 30 N and sliding speed of 1.5 m/s, the untreated ZA27 alloy exhibited a wear rate of 0.006 mm³/m, whereas the aged composite (180°C) achieved a 41.67% reduction (0.0035 mm³/m). Similarly, the COF decreased from 0.48 to 0.38, reflecting a 20.8% reduction in friction. Aging at 180°C provided the best wear resistance, while temperatures beyond 180°C led to over-aging, reducing wear performance.