Addition of Beryl Content to Aluminum 2024 Alloy Influencing the Slide Wear and Friction Characteristics

Abstract

The metal matrix composites (MMCs) especially aluminum-based composites have made greater impact in automobile and aerospace industries in view of possessing inherent properties, such as lower density, higher stiffness, good wear resistance and reduced friction levels. These are achieved through the introduction of different types of reinforcements/fillers in the matrix to achieve tailor-made properties. The various ceramic reinforcements like alumina, silicon carbide, zirconia, graphite, molybdenum di-sulfide, fly ash, etc., have contributed to the enhancement in the properties. For example, the graphite addition to a matrix improves the wear resistance and lowers the friction levels because of its self-lubricity effect. The adoption of other types of reinforcements/fillers such as silicon carbide, silica, alumina, Beryl, and aluminide in the matrix has yielded higher hardness and lower wear losses. A lot of efforts have gone in by various researchers to prove the beneficial effect of adding Beryl particles at different levels to the aluminum matrix, and the results are quite encouraging. In this context, the tribological response of MMCs consisting of aluminum 2024 (Al2024) matrix together with Beryl particles as reinforcements produced by stir casting technique has been studied in detail as Beryl is a hard substance and favors wear resistance and coefficient of friction. The wear and friction tests have been conducted using a Pin-On-Disc (POD) test setup, and the load employed is in the range 49 to 136 N with a sliding speed of 320 rpm. The information on this is infrequent to come across especially the aspect of the higher load applications in POD. Further, the worn-out surface features due to the sliding action have been examined and assessed using scanning electron microscopy (SEM). Recourse of supporting tests such as X-ray diffraction, hardness, noting of surface roughness and light microscopy has been resorted to substantiate the results. It is observed from the data there is a drop in wear loss of about 1.8 to 2.2 times and coefficient of friction reduced by about 1.25 to 1.3 times in comparison of A0 and A6 samples. Based on this work, a good correlation has emerged among the load applied, the sliding speed and its distance employed and the type and content of reinforcement adopted in the aluminum matrix.