Multi Criteria Optimization of Al/Al2O3 Functionally Graded Composite Fabricated Using Grey Relational Analysis

A six-layered Al/Al2O3 functionally graded composite material (FGCM) was successfully fabricated via powder metallurgy (PM), with each layer approximately 1.5 mm. thick. The influence of varying Al2O3 volume fractions on the microstructure, hardness and tribological properties (wear rate, specific wear rate, relative wear resistance and coefficient of friction) was systematically evaluated. Grey Relational Analysis (GRA)was effectively utilized for multi-criteria optimization, revealing that, relative wear resistance significantly influences the wear stability of the FGCM. Optimal performance was achieved at an intermediate Al/ Al2O3 fraction (e.g., 30%), resulting in notably enhanced wear resistance. The study demonstrates the efficacy of integrating PM fabrication and GRA optimization in producing FGCMs suitable for demanding applications in automotive and aerospace industries.