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采用Gleeble-3500热模拟试验机对轧态Nitinol 60形状记忆合金进行等温恒应变速率拉伸试验,基于动态材料模型的加工图技术,研究了该合金在650~850℃和0.01~1 s~(-1)范围内的高温变形特性,并优化了其适宜的高温变形参数范围。结果表明,加工图中失稳区位于低温、高应变速率区,范围为650~776℃、0.075~1 s~(-1),对应的失稳现象为局部塑性流动。加工图中有2个η峰值区,范围分别为690~750℃、0.01~0.026 4 s~(-1)和750~838℃、0.01~0.050 5 s~(-1),η最大值分别达到了0.36和0.38,对应的变形机制均为动态再结晶,这2个区域为Nitinol 60合金适宜的热拉伸变形工艺参数范围。
The isothermal constant strain rate tensile test was conducted on the rolled Nitinol 60 shape memory alloy by Gleeble-3500 thermal simulator. Based on the processing diagram of the dynamic material model, the microstructure and mechanical properties of the alloy at 650-850 ℃ and 0.01-1 s ~ -1) range of high temperature deformation characteristics, and optimize the appropriate high temperature deformation parameters range. The results show that the destabilized zone is located in the low temperature and high strain rate region, with the range of 650 ~ 776 ℃ and 0.075 ~ 1 s ~ (-1). The corresponding instability is local plastic flow. There are two peak areas of η in the processing map, ranging from 690 to 750 ℃, 0.01 to 0.026 4 s -1 and 750 to 838 ℃, 0.01 to 0.050 5 s -1, 0.36 and 0.38, corresponding to the deformation mechanism are dynamic recrystallization, these two regions for the Nitinol 60 alloy suitable hot tensile deformation process parameters.