Fabrication and Investigations on Physical Mechanical Tribological Characteristics of Al6061 B4C and Al6061 Si3N4 Metal Matrix Composites

Abstract

The driving force for the utilization of Aluminum (Al) metal matrix composites (MMCs) over ferrous and nonferrous alloys like brass and bronze materials is due to the economic, performance and environmental benefits. Low noise, low emissions from aerospace vehicles and low consumption of fuel are the benefits in the transportation sector. With constant research in this field, improved fabrication techniques have evolved, and this has led to the use of these Al-based composite materials instead of most of the monolithic materials in aerospace, marine and automobile applications. There is a rapid growth in the industrial domain and hence an increased demand for new materials. Conventional metals and alloys have limitations to achieve the hardness property as required in the applications where wear is the critical design criteria. Therefore, the material researchers are focusing on MMCs rather than on monolithic materials to obtain advanced materials with superior properties. Al-MMCs are one in which, one of the materials is Al or its alloy, which is the matrix, and the other is a reinforcement, which is dispersed in the matrix. The reinforcement materials usually are fibers, whiskers, and particulates. The most used reinforcement is the ceramic since they have properties such as higher density, high level of hardness and thermal stability. However, they have limitations such as low wettability and low compatibility with Al metal matrix. The main fabrication techniques for Al-MMCs are liquid and powder metallurgy. All the mentioned fabrication techniques are suitable, but economically, stir casting is the most beneficial, especially for mass production. A key challenge in the fabrication of Al-MMCs is to homogeneously distribute the reinforcement to achieve a defect-free microstructure and thus increasing the hardness. Al-MMCs reinforced with particulate extend improved mechanical properties and wear resistance. In most products, there exist circumstances where two coupling..