Coupled size and temperature effects on intermittent plasticity of BCC micro-crystals
Coupled size and temperature effects on intermittent plasticity of BCC micro-crystals
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DOI：
10.1016/j.actamat.2023.119201
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发表时间：
2023-08
期刊：
影响因子：
9.4
通讯作者：
Peng Zhang;P. Cheng;Jinyu Zhang;Gang Liu;J. Weiss;Jun Sun
中科院分区：
文献类型：
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作者：
Peng Zhang;P. Cheng;Jinyu Zhang;Gang Liu;J. Weiss;Jun Sun
The intermittent plasticity of pure Mo microcrystals with diameters from 500 to 3500 nm was studied using micro-pillar compression methodology at temperatures ranging from 25 °C to 200 °C, in order to explore its dependence on external size and temperature.技术背景是BCC金属在微电子等需要小型化的现代领域制造高温部件的潜在价值。我们从荒野度、雪崩尺寸分布和爆发峰值速度方面分析了塑性涨落。 This reveals coupled size and temperature effects on a mild-to-wild transition: the transition temperature decreases with decreasing sample diameter, while the transition diameter increases with rising temperature. In addition, strain-rate sensitivity tests were conducted, implying that mild plasticity is associated to screw dislocation motions controlled by thermally activated nucleation of kink-pairs, whereas wild plasticity is nearly athermal. This experimental observation is interpreted by a damping effect of the thermally activated motion of screw dislocations on the propagation of avalanches. From this, we propose a controlling parameter based on a simple dislocation source model, which unifies the coupled sample size and temperature effects on the mild-to-wild transition, and which could be of practical significance for microscale applications.
The intermittent plasticity of pure Mo microcrystals with diameters from 500 to 3500 nm was studied using micro-pillar compression methodology at temperatures ranging from 25 °C to 200 °C, in order to explore its dependence on external size and temperature. The technological background is the potential value of BCC metals in the manufacture of high-temperature components in modern fields requiring miniaturization, such as microelectronics. We analyzed plastic fluctuations in terms of wildness, avalanche size distribution, and burst peak velocity. This reveals coupled size and temperature effects on a mild-to-wild transition: the transition temperature decreases with decreasing sample diameter, while the transition diameter increases with rising temperature. In addition, strain-rate sensitivity tests were conducted, implying that mild plasticity is associated to screw dislocation motions controlled by thermally activated nucleation of kink-pairs, whereas wild plasticity is nearly athermal. This experimental observation is interpreted by a damping effect of the thermally activated motion of screw dislocations on the propagation of avalanches. From this, we propose a controlling parameter based on a simple dislocation source model, which unifies the coupled sample size and temperature effects on the mild-to-wild transition, and which could be of practical significance for microscale applications.