Evaluation of microstructure and mechanical properties of Al1050/Al2O3/Gr composite processed by forming operation ECAP

Enhancement of microstructure and mechanical features of the hybrid aluminum matrix composite (HAMC) prepared by the stir-casting process (SCP) is quite significant for failure prevention during the service. In this work, the circular rod of hybrid aluminum matrix composite reinforced with particles of alumina (Al2O3) 50 mu m, and graphite (Gr) 40-100 mu m fabricated by SCP was adopted. This Al1050/Al2O3/Gr composite was subjected to severe plastic deformation using equal channel angular pressing (ECAP) at room temperature to show the impact of this process on the microstructure and mechanical features of the fabricated composite. Grain refinement, strength, and hardness were evaluated at different forming passes (1P, 3P, and 5P) with two channel angles (die angles) of 120 degrees and 135 degrees. The results revealed that the number of ECAP cycles has a significant effect on the refinement of the grain size. The fifth pass of ECAP (5P ECAP) with a die angle of 120 degrees gave more refinement of the grains in the range of 36-75 nm compared to other passes. On the other hand, the strength and hardness relatively augment until 5P ECAP with increasing the cycle number at two die angles of 120 degrees and 135 degrees. The ultrafine grain can reduce the voids of the aluminum matrix then the hardness is enhanced.