铁在范性形变过程中的低频内耗

在改装了的拉力试验机上测量了纯铁在范性形变过程中的内耗。研究了拉伸速率(在0.73×10^-6-50×10^-6/秒范围内)、测量频率(在0.3—3.6/秒范围内)、应变退火及含碳量等对纯铁范性形变过程中内耗的影响。所得结果表明,在屈服平台上,范性形变过程中内耗基本不变,且其值随范性形变速率的增加和测量频率倒数的增加而线性增加。将实验结果与范性形变过程内耗的位错动力学模型所得出的定量关系式进行了对比,得到了满意的符合。求得了退火纯铁在屈服平台上的位错动力学指数为10关键词：

LOW FREQUENCY INTERNAL FRICTION OF IRON IN THE PROCESS OF PLASTIC DEFORMATION

The internal friction of Armco-iron in the process of plastic deformation was measured by a middle torsion pendulum on a modified tensile testing machine. The effects of strain rate (in the range of 0.73×10^-6/sec to 50×10^-6/sec), frequency (0.30/sec to 3.6/sec), annealing and carbon content on the internal friction were studied. The results showed that on the yielding plateau, the internal friction did not change with the strain, but increased linearly with the increase of strain rate and varied inversely with frequency. In comparing the data with the theoretical expression derived from the dislocation dynamic model of internal friction in the process of plastic deformation, it is shown that the dynamic model is in good agreement with the experimental results. The dislocation dynamic exponent m of Armco-Fe derived from this model is 10.8-12.3, which is reasonable.The range within which the dislocation dynamic model holds is also discussed.