Effects of the T6 heat treatment on the tribological behaviors of SiCp/7055Al composites

Abstract

This study investigates the effects of T6 heat treatment on the dry sliding tribological behaviors of SiCp/7055Al composies under different temperatures and loads. SiC particle reinforced aluminum matrix composites (AMCs) with a volume fraction of 17% were prepared by spray deposition (SD). For T6 heat treatment composites were heated at 475 ℃ for 2 h and artificially aged at 120 ℃ for 28 h. The wear morphology, wear debris and cross-sectional microstructure and element distribution of the worn surface were characterized by energy dispersive spectrometer (EDS) mapping attached to the scanning electron microscope (SEM). Results show that the T6 heat treatment was effectively refined the coarse precipitation. The hardness of T6 treated composites increased from 72.62 HRB to 93.43 HRB. The coefficient of friction of T6 treated composites was lower and more stable than those for SD composites. The delamination of the composites is alleviated effectively by T6 heat treatment during friction. With the increasing of the loads and temperatures, the wear rates of the T6 treated composites decreases significantly than those for SD composites. The wear mechanism of T6 treated and SD composites are abrasive wear, fatigue wear, adhesive wear and oxidation wear at 100 ℃.