Characterization of the Strain-Rate-Dependent Plasticity of Alloys Using Instrumented Indentation Tests
Characterization of the Strain-Rate-Dependent Plasticity of Alloys Using Instrumented Indentation Tests
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DOI：
10.3390/cryst11111316
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发表时间：
2021-10
期刊：
影响因子：
2.7
通讯作者：
T. Chen;I. Watanabe;T. Funazuka
中科院分区：
文献类型：
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作者：
T. Chen;I. Watanabe;T. Funazuka
仪器压痕试验是表征应力-应变曲线的有效方法，而不是拉伸或压缩试验，最近已被应用于高温下的机械性能的评价。在高温试验中，所施加载荷的速率依赖性似乎是占主导地位的。在这项研究中，应变率相关的塑性在高温下的仪表压痕试验的特点是通过同化的实验与模拟模型。在此基础上，定义了一个简单的应变率相关塑性本构模型，并确定了材料常数，以使高温下的实验结果与相应的模拟结果之间的差异最小。有限元模拟使用几个估计的力学性能进行了比较，在相同的温度下的压缩试验中的相应实验的估计的材料响应的验证。本构模型和确定的材料常数可以再现应变率依赖的材料行为下的各种加载速度在仪表压痕试验，但是，计算模拟的负载水平低于那些在压缩试验中的实验。这些结果表明，在仪表压痕试验中评估的局部机械响应与高温下压缩试验中的体积响应不一致。因此，由于尺度效应，在高温下使用仪器化压痕测试不能表征体积性质。
Instrumented indentation tests are an efficient approach for the characterization of stress–strain curves instead of tensile or compression tests and have recently been applied for the evaluation of mechanical properties at elevated temperatures. In high-temperature tests, the rate dependence of the applied load appears to be dominant. In this study, the strain-rate-dependent plasticity in instrumented indentation tests at high temperatures was characterized through the assimilation of experiments with a simulation model. Accordingly, a simple constitutive model of strain-rate-dependent plasticity was defined, and the material constants were determined to minimize the difference between the experimental results and the corresponding simulations at a constant high temperature. Finite element simulations using a few estimated mechanical properties were compared with the corresponding experiments in compression tests at the same temperature for the validation of the estimated material responses. The constitutive model and determined material constants can reproduce the strain-rate-dependent material behavior under various loading speeds in instrumented indentation tests; however, the load level of computational simulations is lower than those of the experiments in the compression tests. These results indicate that the local mechanical responses evaluated in the instrumented indentation tests were not consistent with the bulk responses in the compression tests at high temperature. Consequently, the bulk properties were not able to be characterized using instrumented indentation tests at high temperature because of the scale effect.