Microstructure, mechanical properties and reciprocal dry sliding wear behaviour of as-cast and heat-treated TiN/Al-7Si functionally graded composite

Abstract

This work explores the effect of T6 heat-treatment on the microstructure, mechanical properties and dry sliding linear reciprocating wear behaviour of Al-7Si/Titanium Nitride (TiN) centrifugally cast functionally graded composite. The 10 wt% TiN particle addition and subsequent eutectic Si spheroidisation due to heat treatment revealed an improvement in microhardness, tensile strength and wear resistance of heat-treated composite when compared to as-cast composite. Reciprocating wear analysis at varying applied loads and sliding distances revealed a combination of specimen micro-ploughing and abrasive particle action at low load and sliding distances, which was in stark contrast to the combination of abrasive and adhesive wear at higher loads and sliding distances. The surface was characterised by mechanically mixed layer formation due to tribo-oxidation, adhesive and delamination wear mechanisms. This composite can be utilised to replace traditional materials employed in reciprocating pump and compressor applications.