Stress analysis around DSCu/SS316 HIP bonded interface

HIP bonded structure of DSCu/SS316 is proposed for ITER plasma facing components. In 20th SOFT, we reported the fracture strength of HIP bonded interface at ambient temperature. But first wall is at high temperature in operation, we estimate in this study the fracture strength of HIP bonded interface at 473K as a first step of high temperature. The results of fracture strength test indicate that the fracture strength of HIP bonded interface at high temperature is lower than that at ambient temperature. The fracture surfaces of specimens ruptured at ambient temperature and at 473K were observed. Crack surfaces were nearly 10 μm apart from the bonded interface into DSCu side. Scanning electron microscope observation is considered to show the existence of the thin new layer in DSCu region in which the dispersed Al2O3 was diminished. Assuming the thin layer to be composed of Cu, fracture behavior of HIP bonded structure is simulated by three layers model DSCu/Cu/SS316 and the fracture strength is estimated by the stress intensity factor K. The analytical results conclude that crack propagates in DSCu/Cu interface more easily, which is good agreement with fracture surface in experiments.