Abstract
The internal friction Q−1 of Fe–Cr alloys containing 0∼35% Cr has been measured by the inverted torsion pendulum at maximum shear strain amplitudes γm of 0.7∼167×10−6 at a frequency of about 1.1 Hz. The value of Q−1 increases gradually up to a certain value of γm, beyond which it increases sharply, goes through a maximum and then decreases. This trend is especially remarkable when the alloys are heated at 1200°C.
In Fe–Cr alloys slow-cooled after heating at 800∼1200°C, the value of Q−1 which shows two maxima at concentrations of 5 and 15% Cr increases with increasing heating temperature. An Fe–15% Cr alloy exhibits the highest Q−1 value of 68×10−3 (γm=80×10−6) when slow-cooled after heating at 1200°C. Besides, the Q−1 value in the rapid-cooled state shows only a maximum at 20% Cr. The change of rigidity modulus with γm is quite similar to that in Q−1. Therefore, the high value of Q−1 of Fe–Cr alloys is thought as being due to the effect of the magnetomechanical hysteresis.
