Moderate temperature wear behaviour of Magnesium-Dicalcium silicate composite

Abstract

This study investigates the effect of dicalcium silicate content on the moderate-temperature wear behaviour of magnesium-dicalcium silicate (AZ91D-Ca₂SiO₄) composites over a temperature range of 100 °C,150 °C, 200 °C and 250 °C. Various wear mechanisms were investigated in AZ91D-Ca₂SiO₄ composites under specific temperature conditions. AZ91D-Ca₂SiO₄ composites were fabricated with different weight percentages (2.5 %, 5 %, and 10 %) of Ca₂SiO₄ reinforcement using the stir casting process. Hardness, phase composition, wear depth, and morphological changes were observed in the composites after wear testing. The metal-oxide interaction regimes were precisely detailed through the tribology characterization. The results demonstrate a significant increase in wear rate as temperatures rise from 100 °C to 250 °C. Specifically, at temperatures around 100 °C and 150 °C, abrasive wear and oxidation were identified as the primary wear mechanisms. At moderate temperatures, around 250 °C, abrasive wear, plastic deformation, and delamination were the dominant wear mechanisms. The higher presence of Mg-Si and Mg-Ca phases, along with Ca₂SiO₄ particles, on the worn surfaces of the composites has reduced the oxidation of the AZ91D matrix at moderate temperatures. Furthermore, this study reports a detailed investigation into the influence of different weight percentages (2.5 %, 5 %, and 10 %) of Ca₂SiO₄ on the moderate-temperature wear behaviour of AZ91D and AZ91D-Ca₂SiO₄ composites.