鋼のAc₁変態前の高温内部摩擦

抄録

The internal friction at higher temperatures before Ac₁ transformation in 0.09, 0.38, and 0.85% carbon steels was measured as a function of temperature, using a torsion pendulum with a frequency of vibration of about 1.9 cycles per second. The internal friction curves in 0.85% carbon steel do not show a peak but continue to rise with the rise of measuring temperature from about 400°C. The activation energy of the process causing the anelastic behaviour was found to be 59,000 to 64,000 calories per mole. The internal friction at a given temperature increases with an increase of the amount of carbide in steel. In recrystallized and tempered steels, the internal friction curves shift toward higher temperatures with the rise of annealing temperature. In addition, the internal friction at a given temperature in fully recrystallized and tempered steels is considerably greater than that in steel annealed fully at above A₃₋₁. Such behaviours are interpreted in terms of the concept of the coupled relaxations of an irregular network of interfaces.