Parametric optimization of hot pressing powder metallurgy process for improved toughness and microhardness of multilayered B4C/AA7075 FGM
摘要
The current study aims to develop a multilayered B4C/AA7075 functionally graded material (FGM) with high impact toughness as well as hardness. The FGM was fabricated through a hot compaction powder metallurgy process. Taguchi's L9 orthogonal array coupled with grey relational analysis was utilized to optimize the critical process parameters such as compaction pressure, temperature, and holding time. Charpy impact toughness and Vickers hardness tests were conducted to evaluate the toughness and microhardness of the specimens, respectively. SEM and EDS analyses were performed on FGM samples to examine their morphology, fractured surfaces, and elemental composition. The results indicated that the significant parameter configuration with a compaction pressure of 550 MPa, a temperature of 400 °C, and a holding time of 30 min achieved the highest grey relational grade, resulting in the development of FGM with improved toughness and maximum microhardness. Further, the optimum GRG result showed an improvement of 30.50% and 19.96% in toughness and microhardness compared to the preliminary run. Microstructural analysis of the optimized sample showed even dispersion of B4C reinforcement particles within the AA7075 matrix, with better bonding between the FGM layers. The fractured surface of optimized FGM exhibited brittle and ductile fracture modes, allowing better energy absorption before failure.