Microstructural and Mechanical Properties of Microwave Sintered AA7075/Graphite/SiC Hybrid Composite Fabricated by Powder Metallurgy Techniques

Effect of Variations in Microwave Processing Temperatures on Microstructural and Mechanical Properties of AA7075/SiC/Graphite Hybrid Composite Fabricated by Powder Metallurgy Techniques

“…It should be noted that the microwave sintering process facilitates the controlled grain growth, grain boundary strengthening and dislocation strengthening mechanisms in the materials, which fundamentally play a major role in strengthening the hybrid composite material. In previous investigation, the addition of graphite as a primary reinforcement and SiC as a secondary reinforcement to AA7075 matrix material sintered through microwave technique showed a mechanical strength of 402 and 457 MPa in tensile and compression, respectively, and accommodated an optimum reinforcement levels of 10% (8%graphite + 2%SiC) in the matrix AA7075 material [28]. In the present work, the addition of SiC as a primary and graphite as a secondary reinforcement particle showed a superior enhancement in the mechanical properties.…”

“…10. In previous investigation, the addition of graphite as primary reinforcement and SiC as secondary reinforcement showed an optimized volume fraction level of 8% graphite + 2%SiC in AA7075 matrix material with a mechanical strength of 357 and 385 MPa in tensile and compression, respectively, and a hardness value of 99 Hv [28]. In the present work, adding the SiC as primary and graphite as secondary reinforcements showed an optimized volume fraction levels of 7%SiC + 5%graphite in AA7075 matrix material with a mechanical strength of 365 and 451 MPa in tensile and compression, respectively, and a hardness value of 109 Hv.…”

“…Composite powders were prepared in a way to distribute the reinforcement particles in the matrix material uniformly. To distribute the reinforcement particles in the matrix material uniformly, ball milling techniques with proper milling parameters were used; those are listed in Table 2 [28,[33][34][35].…”

“…The cold compacts were placed at centre of cavity, and sintering was performed at the multimode cavity [10,28,29,36]. Figure 2 represents the dimensions of composite samples for mechanical tests after sintering and machining operations.…”

“…Microwave sintering is one of the most suitable sintering techniques for particle-reinforced metal matrix composites due to the rapid internal heat generation phenomenon in ceramic particles by absorbing the microwaves. Heat generation takes place inside the powder particles by the oscillation of dipoles at microwave frequencies (300 MHz to 300 GHz) [10,28,29]. Microwave heating phenomenon depends on the response of a material to alternating electric and magnetic elds of microwaves.…”