Effect of casting process on microstructure and tribological behavior of LM13 alloy

Abstract

LM13 alloy is widely used in piston industry, due to its low coefficient of thermal expansion, excellent castability and hot tear resistance. In this research effect of casting process on wear behavior of LM13 alloy was investigated. First, samples were produced using two casting processes and heat treated. Then wear behavior of these samples under dry sliding condition was examined. Results of hardness and strength tests indicated that squeeze cast specimens exhibited higher mechanical properties. Wear experiment results showed that in both squeeze and gravity cast specimens, amount of weight loss increases with increase in sliding distance which is accompanied by reduction in wear rate and friction coefficient. A comparison between two samples demonstrated that squeeze sample had better tribological behavior. Casting process variation causes decrease in friction coefficient from 0.4 to 0.2 for squeeze cast samples and decrease in weight loss of these samples. Squeeze cast samples had better surface quality and in these samples abrasive, adhesive and delamination are dominant wear mechanisms while in gravity cast samples abrasive, adhesive and surface fatigue are the dominant wear mechanisms.