抄録
Measurements of Young’s modulus at −150∼400°C and of rigidity modulus and hardness at room temperature have been carried out for Mn–Cu–Co alloys subjected to a variety of heat treatment and cold working conditions. It is shown that the ternary alloys slow-cooled after heating at 900°C for 1 hr reveal anomalous changes associated with antiferromagnetic\
ightleftarrowsparamagnetic transformation on the Young’s modulus at room temperature curves. The Young’s modulus at room temperature does not show any appreciable difference by the state of annealing, cold working or water quenching while the Mn and Co concentrations are relatively small. The difference becomes conspicuous as the Mn or Co concentration is increased. The temperature coefficient of Young’s modulus undergoes a marked variation by annealing, cold working, water quenching, and reheating after cold working or water quenching as well as with alloy composition. It is also to be noted that the temperature coefficient of Young’s modulus vs composition curves show large maxima in positive and negative signs, thus indicating the Elinvar characteristics. The rigidity modulus and its temperature coefficient at room temperature represent a very analogous variation to that of Young’s modulus and its temperature coefficient with composition, heat treatment and cold working. The values of hardness are higher in the state of reheating after cold working or water quenching than those in the state of annealing, cold working or water quenching, and the corrosion resistance is fairly satisfactory.
