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Three-dimensional microstructure observations, macro- to micro-scopic residual stress measurements by three methods and creviced bent beam SCC tests were performed for Inconel/low alloy steel (LAS) weld samples. The possible reasons for the suppression of SCC crack propagation near the weld interface found at a nuclear power plant were estimated to include the crack branching at the grain boundary (GB) parallel to the interface, i.e., Type II GB, compressive residual stresses in the LAS region and crack tip oxidation in the LAS at the interface. The formation mechanism of Type II GB and stress gradient in individual grains in the Inconel are also discussed.

AlxGa1-xN alloys with x=0.375, 0.398, 0.401, 0.592 and 0.696 were deposited on sapphire substrate by the hydride-vapor-phase epitaxy (HVPE) method. Thermal effusivity measurements were carried out on AlxGa1-xN alloys using a thermal microscope at room temperature. The lag between sinusoidal heating laser wave and thermoreflectance wave was used to measure the thermal diffusivity. Thermal conductivity values of the AlxGa1-xN alloys were also obtained as a function of AIN mole fraction in the alloy. The thermal conductivity was found to decrease with increasing AIN fraction and the experimental data agree with values estimated using the virtual crystal model.