Challenges and Opportunities in Synthesis of Hybrid Cu-Al₂O₃-C and Cu-ZrO₂-C Composites Through Stir Casting Route

Composites have been used by mankind from ages in producing different tools and equipment. Metal matrix composites became popular due to their better mechanical and thermo-physical properties as compared to pure metals and alloys. The aim of the present study is to highlight the key challenges in the synthesis of copper matrix-based hybrid Cu-Al2O3-C and Cu-ZrO2-C composites through stir casting route. The reinforcement varied in composition from 1 wt to 4 wt%. Stir casting as a process for synthesis of metal matrix composites (MMCs) has gained popularity due to its cost effectiveness and simplicity. Stir casting involves the mixing of reinforcement with the molten metal matrix through stirring in a furnace and then pouring it in a die for solidification. This liquid metal process requires careful execution and control over the parameters in order to produce the high quality MMCs. Stir casting process has some limitations associated with it such as nonuniform dispersion, agglomeration of reinforcement particles, formation of oxides and intermediate phases, porosity and cracks. This paper brings to the fore these limitations and suggests the ways to improve the process so that desired properties can be obtained in the composite. This work also generates the opportunities for the development of new and innovative alternatives to overcome the challenges associated with stir casting in synthesis of MMCs.