Influence of zirconium carbide particles on the mechanical characteristics of heat treated Al7475 alloy

Aluminium alloys exhibits excellent properties and therefore they are used broadly in automobile, aviation, and defence sectors. The studies on the effect of zirconium carbide (ZrC) particulates on the mechanical properties of heat-treated stir-cast Al7475 alloy are still in the initial stage. Hence, the present study is aimed at the study of microstructure and mechanical characteristics of as-stir-cast and heat-treated stir-cast Al7475-ZrC composites. The zirconium carbide particulates concentration ranges from 2 to 8 wt% in Al7475 alloy. The Al7475 alloy and Al7475-ZrC composites were T6 heat-treated. Both the Al7475 alloy and the Al7475-ZrC composites have undergone significant microstructure refinement owing to heat treatment. The SEM micrographs of heat-treated stir-cast Al7475-ZrC composites have revealed that the matrices of Al7475 composites consisted of a fine dispersion of uniformly distributed ZrC particles that eventually resulted in a considerable improvement in the properties of composites. The mechanical properties of heat-treated stir-cast Al7475-ZrC composites were superior to that of as-stir-cast Al7475-ZrC composites. The optimum values of UTS of as-stir-cast and heat-treated stir-cast Al7475-ZrC composites are 104.42 N/mm² and 121.95 N/mm², correspondingly. The optimum values of compression strength of as-stir-cast and heat-treated stir-cast Al7475-ZrC composites are 665.43 N/mm² and 789.68 N/mm², correspondingly. The optimum values of the hardness of as-stir-cast and heat-treated stir-cast Al7475-ZrC composites are 103.74 BHN and 126.86 BHN, respectively. The optimum values of impact strength of as-stir-cast and heat-treated stir-cast Al7475-ZrC composites are 16 J/mm² and 19 J/mm², respectively. Among heat-treated stir-cast composites, Al7475-6%ZrC composite has the highest enhancement in mechanical characteristics, and the UTS, compression strength, and hardness are 15%, 16%, and 18% higher than that of as-stir-cast Al7475-6%ZrC composite and 19%, 14% and 10% higher than that of heat-treated stir-cast Al7475 alloy respectively.