Effect of Multi-Axial Forging on Mechanical Properties and Microstructures of AA7075/TaC Composites

Abstract

Abstract The objective of the current work is to develop a AA7075 reinforced Tantalum Carbide (1, 3, 5, and 7 wt%) composite through stir casting. The secondary process such as Multi-axial forging (MAF) followed by ageing was performed on AA7075/5TaC(S-4) composite to enhance the strength and ductility of composite. The evolution of microstructures were examined by Optical microscope (OM) and Field emission scanning electron microscopy (FESEM) and the MAF process was analyzed by Electron back scattered diffraction (EBSD). The microstructure characterization reveals that refinement of grains take place with the addition of TaC due to the pinning effect. The microstructure of the MAF shows suppression of dynamic recovery and generation of dislocation density because of strain energy effect at room temperature. The mechanical properties were measured by Vickers hardness and universal tensile testing machine and obtained as the highest for 5 wt % TaC which is 142 Hv, 211 YS, and 254 UTS. MAF specimen shows an improvement in mechanical properties and percentage elongation compared to properties obtained in S-4 composite specimen. The highest UTS, YS, and % Elongation of S-4 specimen was achieved with MAF+aged when the cumulative strain was up to 4.8. The enhancement in hardness and tensile strength of the developed composite and MAF specimen were discussed with various strengthening mechanisms.