Enhanced Performance of AA7075/SiC/ZrC Hybrid Composite through Microwave Assisted Powder Metallurgy Techniques

In the present work, ball milling followed by conventional and microwave sintering was used to develop AA7075/SiC/ZrC hybrid composites. Microwave sintering was performed on the optimized volume fractioned AA7075/SiC/ZrC hybrid composite. Addition of ZrC particles to the optimized AA7075/SiC composite improved performance up to 2% ZrC level. The microwave sintered S8Z2 (8% SiC + 2% ZrC) composite exhibited ultimate tensile and compressive strengths of 461 and 510 MPa, respectively, and the same composite sintered through a conventional technique showed maximum tensile and compression strengths of 375 and 420 MPa. Microwave sintered composites with an average grain size of 4.99 mu m did not lead to secondary phase generation. A Conventionally sintered composite with an average grain size of 8.59 mu m has been shown to have an Al3Zr secondary phase. Restricting grain growth due to quick sintering times, low temperatures, and rapid heating rates promoted grain boundary and dislocation strengthening mechanisms. The generation of the Al3Zr secondary phase degraded the mechanical properties of the conventionally sintered composite. Microwave sintered composites had low pore levels due to uniform heat distribution and a small allowance for the thermal mismatch. A conventionally sintered S8Z2 composite showed a pore level of 2.89%, while a microwave sintered composite showed a pore level of 1.39%, representing densification through rapid diffusion in microwave processing. Overall, the microwave sintered optimized hybrid composite showed an enhancement of 184.5% and 118% in tensile and compression strengths when compared to the base alloy material.