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用扭摆测量淬硬碳钢的内耗,当测量温度由室温渐渐升高时,在130℃附近有一个内耗峰出现。当温度达到170℃后再降温测量,这个内耗峰完全消逝不见。上述的现象在含碳0.29％到1.4％的几种淬硬碳钢和淬硬滚珠钢中都曾经看到。由内耗峰的出现可以认为马氏体在第一个回火阶段中的转变产物(ε-碳化铁)与母体具有共格性,由于共格界面的应力感生运动而引起内耗。 曾用具有马氏体组织的0.25％碳钢试样作实验,没有观测到上述的内耗峰。但是当回火温度达到280-300℃以后,在降温或升温测量中都观测到一个内耗峰(在150℃附近)。这表示低碳马氏体在第三个回火阶段中的转变产物与母体具有共格性。但是由于这个内耗峰的表现与上述高碳试样的内耗峰不同,所以我们认为这转变产物并不是ε-碳化铁。
To measure the internal friction of hardened carbon steel with a twist, when the measured temperature gradually increases from room temperature, there is a friction peak near 130 ° C. When the temperature reached 170 ℃ before cooling measurement, the internal friction peak disappeared completely disappeared. The above phenomenon has been seen in several hardened carbon steels and hardened steel balls from 0.29% to 1.4% carbon. From the appearance of internal friction peaks, the transformation product (ε-iron carbide) of martensite in the first tempering phase can be considered to be coherent with the matrix and lead to internal friction due to the stress-induced motion of the coherent interface. Experiments with 0.25% carbon steel samples with martensite have not been observed. However, when the tempering temperature reached 280-300 ° C, an internal friction peak (around 150 ° C) was observed during the cooling or heating measurement. This means that the transformation products of low-carbon martensite in the third tempering phase are coherent with the parent. However, since the internal friction peak behaves differently from the internal friction peak of the high-carbon sample, we believe that this transition product is not ε-iron carbide.