The Effect of Creep Test Temperature on Creep Rupture Properties of α-ray Irradiated AISI 316 Stainless Ste

Abstract

Since it is known that helium bubbles deteriorate the mechanical properties of stainless steel used as a fuel cladding in fast-breading-reactors, the effect of helium was studied.
Thin plate specimens of type 316 stainless steel with helium content of 7.5×10^-6 atom fraction which had been injected by α-ray irradiation from a cyclotron were creep-rupture tested at 550, 650 and 750°C.
The presence of helium caused large reductions in rupture life and elongation as test temperature in creased. The loss of ductility showed to be constant at one test temperature.
By observing fracture surfaces with optical and scanning electron microscope, the difference between the specimen with or without containing helium was clear, and it was shown that the embrittling effect of helium resulted from its tendency to concentrate at grain boundaries, leading to intergranular cracking.