Effect of load and reciprocating velocity on the transition from mild to severe wear behavior of Al-Si-SiC_p composites in reciprocating conditions

摘要

In the present paper, the effect of normal load and reciprocating velocity on transition from mild to severe wear of A319/15%SiC_p, A336/15%SiC_p, and A390/15%SiC_p composites have been reported. Composites were produced through liquid metal metallurgy route. Adhesive wear behavior of composites was studied under dry reciprocating conditions using indigenously developed reciprocating friction wear test rig conforming to ASTM Standard G133-05. It was found that increase in normal load increases wear rate and depending upon the reciprocating velocity and type of composites, mode of wear changes from mild oxi-dative to severe metallic wear was noticed. The load corresponding to the transition from mild to severe wear usually termed as transition load was found to decrease with increase in reciprocating velocity and reduction in silicon content in the alloys used for the development of Al-Si-SiC_p composites. At 1 m/s reciprocating velocity, the transition load for A319/15%SiC_p, A336/15%SiC_p and A390/15%SiC_p composites were found to be in the range of 60-90 N, 60-105 N and 60-120 N respectively. Scanning electron microscope (SEM) study of wear surface and wear debris were conducted to analyze the mode of wear and operating wear mechanism. Severe wear was characterized by massive plastic deformation and gross material removal while the mild wear was found to be associated with delamination and scoring as main wear mechanisms responsible for material loss. Wear mechanism maps for different Al-(6-18)%Si-15%SiC_p composites were proposed in reciprocating contacts.