Effect of Variation of SiC Reinforcement on Wear Behaviour of AZ91 Alloy Composites

Abstract

In this investigation, the extensive wear behaviour of materials was studied using SiC reinforced magnesium alloy composites fabricated through the stir casting process. The wear properties of AZ91 alloy composites with a small variation (i.e., 3%, 6%, 9% and 12%) of SiC particulates were evaluated by varying the normal load with sliding velocity and sliding distance. The worn surfaces were examined by scanning electron microscope to predict the different wear mechanisms on the pin while sliding on the hard disk in the dry sliding wear test condition. The microhardness of the SiC reinforced AZ91 composites was found to be more than the un-reinforced AZ91 alloy. Pins tested at load 19.62 N, and 2.6 m/s exhibited a series of short cracks nearly perpendicular to the sliding direction. At higher speed and load, the oxidation and delamination were observed to be fully converted into adhesion wear. Abrasion, oxidation, and delamination wear mechanisms were generally dominant in lower sliding velocity and lower load region, while adhesion and thermal softening/melting were dominant in higher sliding velocity and loads. The wear loss, wear rate and coefficient of friction of the SiC reinforced composites were lower than that of the unreinforced alloy. This is due to the fact of higher hardness exhibited by the composites. The wear behaviour at the velocity of 1.39 m/s was dominated by oxidation and delamination wear, whereas at the velocity of 2.6 m/s the wear behaviour was dominated by abrasion and adhesion wear. It was also found that the plastic deformation and smearing occurred at higher load and sliding velocity.

In Situ Formation of ZrB2 and Its Influence on Wear and Mechanical Properties of ADC12 Alloy Mixed Matrix Composites

“…This is due to the presence of embedded hard ceramic particles in the soft matrix. A similar observation on wear behaviours was also reported by Kumar et al [ 20 , 26 ]. The wear rate is proportional to the normal load and sliding velocity.…”

Mechanical and Microstructural Characterization of Friction Stir Welded SiC and B4C Reinforced Aluminium Alloy AA6061 Metal Matrix Composites

“…It was also observed that the friction coefficient increased with an increase in load from 10 N to 20 N (while maintaining a constant velocity of 1 m/s). However, the friction coefficient decreased when the load was further increased to 30 N. This may be attributed to the increased brittleness of the samples [ 5 ]. The wear rate prominently increased with higher loading, and this observation was for all loading ( Figure 8 ).…”

“…The wear rate prominently increased with higher loading, and this observation was for all loading ( Figure 8 ). The wear resistance gets transformed from abrasion to adhesion, reducing the average friction coefficient [ 5 ]. The wear rate of composites increased with the increase in load.…”

“…Particles were homogeneously distributed, and no damage of worn surface was observed for higher load. In few cases, the presence of delamination with intense plastic deformation suggests adhesion wear [ 5 ]. The peaks of O in the EDAX analyses indicate the presence of oxidative driven wear.…”

“…In many industrial applications, aluminium alloys are reinforced with hard ceramic particles to enhance the mechanical properties of aluminium metal matrix composites (Al-MMCs) [ 1 , 2 , 3 ]. Aluminium MMCs are lightweight material accompanied with good thermal and electrical conductivity, high stiffness, hardness, strength, melting point and wear resistance [ 4 , 5 , 6 ]. Due to their higher processing prices, Al-MMCs are deployed only for military weapons and aerospace applications.…”