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用扭摆测量淬硬低碳镍合金钢中的内耗,当振动频率约为每秒2周时,在155℃附近有一个内耗峰出现。这个内耗峰的出现条件是:钢中必须含有马氏体、合金元素和碳。在适当的条件下,铬钢和铬镍钢中也曾观察到这个内耗峰。用含镍29.7％的钢作了系统试验,观察到内耗峰高度与试样中的含碳量成正比。内耗峰的高度由于在较高温度(165℃以上)的回火处理而不断降低。由内耗测量所测得的激活能是25,000卡/克分子。以上的实验结果指出,所观测到的155℃新内耗峰是由于碳在合金马氏体中的应力感生微扩散所引起来的。 提出了一个产生内耗峰的初步模型。假定碳在四角马氏体中是处于00(1/2)型的间隙位置。合金元素原子的存在引起晶体点阵中不均匀的畸变,因而应力的作用便改变了碳原子在热平衡状态下在Fe-C-Fe和B-C-Fe(B是合金元素原子)两种00(1/2)型间隙位置之间的跳动几率。这种应力感生的碳原子运动便引起内耗。用这个模型可以定性地解释所观测到的事实。关于这方面的定量研究正在进行中。
To measure the internal friction in hardened low-carbon nickel-alloyed steel with a twist, when the vibration frequency is about 2 weeks per second, there is an internal friction peak near 155 ° C. The appearance of this internal friction peak is that the steel must contain martensite, alloying elements and carbon. This internal friction peak has also been observed in chrome and chrome-nickel steels under appropriate conditions. The system test was conducted with 29.7% nickel steel, and the internal friction peak height was directly proportional to the carbon content in the sample. The height of the internal friction peak continuously decreases due to tempering at higher temperatures (above 165 ° C). The activation energy measured by internal friction measurement was 25,000 calories per mole. The above experimental results indicate that the observed 155 ° C new internal friction peak is due to the stress-induced micro-diffusion of carbon in the alloyed martensite. A preliminary model of internal friction peak is proposed. It is assumed that carbon is in the 00 (1/2) type of interstitial position in the tetragonal martensite. The presence of alloying elements causes uneven distortion in the crystal lattice, and thus the effect of stress changes the thermal stability of the carbon atoms in both Fe-C-Fe and BC-Fe (B is an alloying element) / 2) type of gap between the probability of beating. This stress-induced movement of carbon atoms causes internal friction. Use this model to interpret the observed facts qualitatively. Quantitative research on this area is underway.