Multi-temperature indentation creep tests on nanotwinned copper
Multi-temperature indentation creep tests on nanotwinned copper
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DOI：
10.1016/j.ijplas.2018.01.016
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发表时间：
2018-05
影响因子：
9.8
通讯作者：
Xusheng Yang;Huiru Zhai;H. Ruan;S. Shi;Tong-Yi Zhang
中科院分区：
文献类型：
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作者：
Xusheng Yang;Huiru Zhai;H. Ruan;S. Shi;Tong-Yi Zhang
本工作进一步发展了压痕蠕变的载荷、时间和温度相关变形的多温度方法。在22 °C（RT）、40 °C、50 °C、60 °C和70 °C五个温度下对纳米孪晶铜（nt-Cu）进行了多温度微压痕蠕变试验。与应力类似，硬度用于衡量压痕蠕变载荷水平，而压痕深度用于表征压痕蠕变变形，蠕变应变率由压痕深度应变率表示。多温度微压痕蠕变试验产生足够大的实验数据，这使得一个新的公式压痕蠕变的发展是可行的。有几个内在的参数，表征材料的微观结构的能力，对负载，时间和温度依赖的变形，它们是应变速率敏感性，非热硬度指数，固有的激活能，和激活体积。应变速率敏感性由一个温度下的等温蠕变数据确定，而其他参数必须由多个温度下的蠕变数据确定。新的公式验证了多温度压痕蠕变试验的数据对nt-Cu。利用所测得的本征参数值对非晶Cu的蠕变机制进行了讨论和分析。
The present work further develops the multi-temperature approach on load, time, and temperature-dependent deformation for indentation creep. Multi-temperature micro-indentation creep tests were carried out on nanotwinned copper (nt-Cu) at five temperatures of 22 °C (RT), 40 °C, 50 °C, 60 °C and 70 °C. In analogy with stress, hardness is used to gauge the indentation creep loading level, while the indentation depth is used to characterize the indentation creep deformation and the creep strain rate is represented by the indentation depth strain rate. The multi-temperature micro-indentation creep tests generate sufficiently large experimental data, which makes the development of a novel formula for indentation creep feasible. There are few intrinsic parameters that characterize the capability of the microstructure of a material against load, time, and temperature dependent deformation and they are the strain rate sensitivity, the athermal hardness exponent, intrinsic activation energy, and activation volume. The strain rate sensitivity is determined from isothermal creep data at one temperature, while the other parameters have to be determined from multi-temperature creep data. The novel formula is validated by the experimental data of the multi-temperature indentation creep tests on the nt-Cu. The creep mechanisms of the nt-Cu are also discussed and analyzed by using the determined values of the intrinsic parameters.