Yield Precursor Dislocation Avalanches in Small Crystals: The Irreversibility Transition
Yield Precursor Dislocation Avalanches in Small Crystals: The Irreversibility Transition
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DOI：
10.1103/physrevlett.123.035501
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发表时间：
2019-07-15
影响因子：
8.6
通讯作者：
Greer, Julia R.
中科院分区：
文献类型：
--
作者：
Ni, Xiaoyue;Zhang, Haolu;Greer, Julia R.
晶体金属从弹性到塑性变形的转变与其他非平衡系统（如胶体悬浮液）在外部载荷下的历史依赖性和标度不变的雪崩签名相同。这些其他系统表现出明显的类比加工硬化和屈服应力的过渡，与许多典型的经历纯弹性行为后，通过反复的循环加载“训练”;在这些其他系统的研究表明，幂律缩放的磁滞回线的范围和训练时间的峰值负荷接近所谓的可逆到不可逆的转变（RIT）。我们发现，在这里，小晶体的变形共享这些关键特性：屈服和滞后在单轴压缩实验单晶铜纳米和微米柱反复循环加载下衰减。的振幅和衰减时间的产量前体雪崩发散的峰值应力接近每个支柱的破坏应力，幂律缩放几乎等同于RIT在其他非平衡系统。
The transition from elastic to plastic deformation in crystalline metals shares history dependence and scale-invariant avalanche signature with other nonequilibrium systems under external loading such as colloidal suspensions. These other systems exhibit transitions with clear analogies to work hardening and yield stress, with many typically undergoing purely elastic behavior only after "training" through repeated cyclic loading; studies in these other systems show a power-law scaling of the hysteresis loop extent and of the training time as the peak load approaches a so-called reversible-to-irreversible transition (RIT). We discover here that deformation of small crystals shares these key characteristics: yielding and hysteresis in uniaxial compression experiments of single-crystalline Cu nano- and micropillars decay under repeated cyclic loading. The amplitude and decay time of the yield precursor avalanches diverge as the peak stress approaches failure stress for each pillar, with a power law scaling virtually equivalent to RITs in other nonequilibrium systems.