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作为航空发动机涡轮盘用新型材料,镍钴基变形高温合金在300～600℃温度区间内拉伸时会产生Portevin-Le Chatelier(PLC)效应。本文采用数字散斑相关方法,研究了镍钴基变形高温合金在400℃下拉伸变形过程中伴随PLC效应出现的应变局域化现象,即PLC带。实验结果表明,PLC带内的应变比试件平均应变大一个数量级,而带外部分应变接近于零。同时还观察到了带外部分的弹性收缩现象,即出现应变为负的区域。在拉伸全程中,PLC带与拉伸轴方向成约60°的夹角。PLC带的宽度均为4～4.5mm,远大于试件最小尺寸(厚度),这一点与铝合金中的带宽与试件最小尺寸相近这一现象截然不同。
As a new material for aero-engine turbine disks, the Portevin-Le Chatelier (PLC) effect occurs when a nickel-cobalt based superalloy is stretched at a temperature in the range of 300-600 ° C. In this paper, the digital speckle correlation method is used to study the strain localization caused by the PLC effect during the tensile deformation of Ni-Co-based superalloy at 400 ℃. The experimental results show that the strain in the PLC band is an order of magnitude larger than the average strain of the specimen while the strain in the out-of-band portion is close to zero. At the same time, the phenomenon of elastic contraction of the out-of-band part was also observed, that is, the area where the strain was negative was observed. In the entire drawing process, the PLC has an angle of about 60 ° to the direction of the stretching axis. PLC with the width of 4 ~ 4.5mm, much larger than the minimum size of the specimen (thickness), which is the same with the aluminum alloy bandwidth and the smallest size of the specimen similar to this phenomenon is very different.