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试件塑性变形过程伴随着机械能向热能的转化.利用红外测温法,通过分析红外热像仪采集的温度场图像,系统研究了Al-Mg合金中的Portevin-Le Chatelier(PLC)效应.在不同应变率下,实验得到了三类锯齿形应力-应变曲线,分析了相应情况下试件温度变化曲线的异同及其原因,探讨了三种类型PLC变形带的空间传播特性.研究发现,试件表面的温升随着应变率的增加而增加;PLC带的倾角转向发生在试件的两端或者带外的温度最高处.
The plastic deformation process of the specimen is accompanied by the conversion of mechanical energy to thermal energy.The Portevin-Le Chatelier (PLC) effect in Al-Mg alloys has been studied systematically by analyzing the temperature field images acquired by infrared thermal imager Under different strain rates, three types of zigzag stress-strain curves were obtained, and the similarities and differences between the temperature curves of the specimens under the corresponding conditions and their causes were analyzed. The spatial propagation characteristics of the three types of PLC deformation bands were discussed. The temperature rise of the part surface increases with the increase of the strain rate. The dip angle of PLC belt turns to the temperature of both ends of the specimen or out of band.