Study of Stir Casting and Microstructure of Al-B<sub>4</sub>C MMCs

Abstract

The economic, performance, and environmental advantages of accepting Aluminium (Al) metal matrix composites (MMCs) over steel, cast iron and light alloys are driving forces behind their utilisation. The transportation industry benefits from reduced noise, reduced emissions from airplanes, and reduced fuel use. Continuous research in this field has resulted in improved manufacturing procedures, allowing these Aluminium based composite materials to be used in aerospace industry, marine and vehicle applications rather than most monolithic materials. The industrial sector is rapidly developing, which increases demand for innovative materials. In cases where 'wear' is a critical issue, conservative materials and alloys have limits in reaching the appropriate hard characteristic. Al-MMCs are composite materials that contain Al or an alloy of Al. It acts as the matrix and the reinforcement distributed across the matrix. Common reinforcing materials include fibres, whiskers, and particles. Because of its enhanced density, great hardness, and thermal stability, ceramic reinforcement is the most used. However, they have limits such as less ability to wet and compatibility with the Al matrix. The major production processes for Al-MMCs are powder and liquid metallurgy. All the manufacturing procedures outlined are appropriate, however casting with stir to mix is cost-effective, particularly for big production runs. The distribution of reinforcement evenly to generate a flaw-free structure at micro level and hence raise the resistance to hard behaviour is a critical difficulty in the synthesis of MMCs of Al. Al-MMCs with particle reinforcement have increased mechanical characteristics and wear resistance. Furthermore, the production of MMCs reinforced with particulates is an exciting task, with questions arising due to ductility decline as the weight percent of ceramic particulate reinforcement is increased, gravity segregation due to denser particulates, and oxidation due to the use of Al alloy, which is very susceptible to oxidation. In the present study Al6061-3% B4C MMCs have been developed by stir casting technique. Al6061 is an extruded raw material as purchased from the supplier (and not an ingot) used before remelting and manufacturing the MMCs. The microstructure of the manufactured Al-alloy and Al-MMCs are evaluated. It is observed that stir casting is a suitable method to manufacture Al-MMCs.