Parametric Optimization of Heat Treatment in ZA27/SiC/TiB2 Composite Using MOGA: An Evaluative Study on the Mechanical Performance
摘要
The current work presents a methodology for investigating the upshot of heat treatment on the hardness, ductility and strength of the ZA-27/SiC/TiB2 hybrid metal matrix composite (HMMC). ZA27 alloy is commonly used in applications that demand good strength and bearing resistance. However, the serviceability is restricted to applications where temperatures remain below 100 °C. The addition of SiC and TiB2 particles contribute in evading this gap. Moreover, there is a notable absence of studies focusing on the optimization of the heat treatment process to enhance the strength and hardness of this hybrid composite material. Addressing this critical research gap is the primary objective of the present study. Through a systematic investigation, this work aims to establish a detailed understanding of how heat treatment parameters influence the mechanical properties of the composite. The composite was made through the mechanical stir casting process by reinforcing the alloy with 7.5% SiC and 7.5% TiB2. The first part of the work is to find out strength, hardness and ductility of the nine heat treated specimens. The results of the strength and hardness tests indicated an improvement in its values as the solutionizing time is increased from 3 h to 5 h. However, achieving maximum strength and hardness necessitates precise optimization of the aging time and aging temperature. The results also indicated that prolonged aging could degrade these properties owing to the effect of overaging. An increased solutionizing duration and aging temperature led to an improvement in the hardness and strength without losing much degree of ductility of the composite unlike in case of ZA27 alloy. The subsequent part is purely devoted to optimize the heat treatment variables solutionizing time, aging time and aging temperature to maximize the properties under consideration. A Taguchi L9 orthogonal array was employed to design the experiments in this phase. The regression equations were formed in MINITAB and these equations were subsequently analyzed using a Multi-Objective Genetic Algorithm (MOGA) which generates a Pareto frontier of optimal alternatives. These alternatives were well assessed using different Multi criteria Decision Making techniques TOPSIS, GRA and FUZZY to yield the best possible solution. The fuzzy approach assigned moderate importance to all the objectives, enabling it to converge on a balanced solution. In contrast, the other two techniques prioritized maximizing strength and hardness as their primary objectives, resulting in nearly a unique optimal solution. This shows that the fuzzy approach is unique because it focuses on balancing multiple objectives instead of prioritizing specific ones. The optimal values obtained through the decision making technique are the Vicker’s hardness number 123.5, Ultimate Tensile Strength of 319.2 MPa and the percentage elongation of 7.2 at the solutionizing time − 5 h, aging temperature − 153 °C and aging time − 1 h.