Fracture Properties at Elevated Temperatures of Ferritic Ductile Cast Irons

Both ferritic ductile cast irons with the Mg/P compositional ratios of 0.6 and 2.2 were tensile tested at 673 K. Specimens with the Mg/P ratio of 2.2 showed lower tensile elongation of 5% at 673 K ， which meant the embrittlement was caused by intergranular fracture. In contrast ， impact tested specimens showed the lowest absorbed energy in the temperature range of 973 to 1073 K ， which correspcmded to the embrittlement at 673 K in tensile tests. It was found that temperatures showing embrittlement increased as the strain rate increased due to differences in experimental methods.