Fabrication and Mechanical Properties of Al_2O_3-SiC/TiC/Ni Functionally Graded Materials by SHS/HIP(Materials, Metallurgy & Weldability)
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Dense Functionally Graded Materials (FGMs) in the systems of Al_2O_3/TiC/Ni and Al_2O_3-SiC/TiC/Ni were fabricated by SHS/HIP. Due to the rapid high temperature heating and the use of effective additives, the grain growth could be well controlled. The residual stress produced in the outer Al_2O_3 and Al_2O_3-SiC layers, which was induced by the thermal expansion mismatch between the inner TiC/Ni and the outer ceramic layers, was in the range of -220MPa to -500MPa. Two methods were used to measure the R-curve behavior of FGMs. For the indentation-strength method, the compressive stress of the outer ceramic layers showed steep R-curve behavior. For the single edge notch bend (SENB) method, the toughness of the FGM increased in the compression area and reached its maximum of 33MPam^<1/2> at the interface of the compressive stress and the tensile stress areas. In the tension area the value of toughness decreased.
- Transactions of JWRI
Transactions of JWRI 29(2), 37-44, 2000-12