The application of the J-integral to small specimens of ductile material to be exposed to high temperatures and high levels of irradiation

An investigation of the J-integral as a fracture characterisation for ductile metals in small test specimens is discussed. A stainless steel used in nuclear reactor construction and an aluminium alloy were used in this investigation to see if there might be any limiting size below which the J-integral becomes inaccurate. The results indicate that this lower limit in size can be defined, particularly for the stainless steel, and that it is not as low as might be desired for development of a system of simple, economical, special environment testing. Some comments are made about crack opening displacement measurements. (author)