Effect of SiC addition to the mechanical properties of Al2O3/TiC/Ni symmetric functionally graded materials
Tanihata Kimiaki; Li Zhensi; Miyamoto Yoshinari
Abstract:Symmetrically graded materials of the Al2O3- SiC/TiC/Ni/TiC/SiC-Al2O3 system were fabricated by SHS/HIP. Strong residual compressive stress can be induced in the outer layer due to the thermal expansion mismatch between the outer and inner layers, resulting in simultaneous enhancement of hardness, toughness and strength of the outer layer. The dispersion of SiC in the outer Al2O3 layer increased the residual stress comparing with the Al2O3/TiC/Ni/TiC/Al2O3 system because the thermal expansion coefficient of the outer layer was reduced with SiC having smaller thermal expansion coefficient than Al2O3. Stress analysis was carried out for both systems by means of finite element method, and the relations of the internal stress distribution and mechanical properties were discussed. Key Words:Al2O3-SiC/TiC/Ni/TiC/Al2O3-SiC, symmetrically graded structure, residual compressive stress, SiC particle dispersion, stress analysis by FEM