AbstractTo clarify the physical and mechanical properties of nickel based alloys (Alloy 600 and 690), the effects of chromium carbides on the electrical resistivity and hardness were examined after low temperature aging following cold working. In Alloy 600, chromium carbide precipitates were dispersed at grain boundaries and within the grains and the electrical resistivity and hardness increased markedly after short time aging. In Alloy 690, chromium carbides precipitated mainly at grain boundaries and the increases in electrical resistivity and hardness were relatively small, even after long aging times. The most probable mechanism causing the large increases in electrical resistivity in Alloy 600 is the segregation of solute atoms, such as carbon and nitrogen atoms, to dislocation loops around chromium carbides introduced by cold working.MST/939