Mechanical Properties and Phase Transition of Tungsten with Edge Dislocation under Intensively-Electronic Excitation
Mechanical Properties and Phase Transition of Tungsten with Edge Dislocation under Intensively-Electronic Excitation
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DOI：
10.1016/j.jnucmat.2022.153540
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发表时间：
2022-01
影响因子：
3.1
通讯作者：
J.R. Wang;B. Pan
中科院分区：
文献类型：
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作者：
J.R. Wang;B. Pan
在超快激光和快离子的强烈照射下，像钨这样的金属材料不是处于电子基态，而是处于激发态。在激发态下，系统的性质随激发程度的变化而发生有趣的变化。揭示其性质随激发强度的变化规律，揭示性质变化的物理本质，对于金属材料在极端环境中的应用具有重要意义。本文通过对电子激发的含钨刃位错的紧束缚计算发现，随着电子激发强度的增大，体系的体弹性、剪切弹性和杨氏模量变差，延性先变好后变差。我们认为这一行为源于原子之间的电子激发态削弱了成键强度。此外，还发现在这些弹性性质的演化过程中，体系在电子激发态发生固-固相变，电子激发能约为1.21 eV。我们发现，这种结构相变本质上是由激发两个软声子模驱动的。
Under intensive irradiation of ultrafast laser and swift ions, a metal material like tungsten is not in electronic ground state but in excited states. In the excited states, the properties of system intriguingly evolve with the degree of excitation. Revealing how its properties change with the degree of excitation and uncovering the physical nature in the change of properties are of great importance for application of the metal materials in some extreme environment. In this work, through performing tight-binding calculations on the electronically-excited tungsten containing edge dislocation, we found that as the electronic excitation of the system becomes heavier, its bulk modulus, shear modulus, and Young's modulus become worse, and its ductility gets better first and then turns to be worse. We proposed that this behavior is originated from the bond strength weakened by the electronically-excited states between atoms. Furthermore, it is found that during the evolution of these elastic properties, a solid-solid phase transition in the system happens at the electronically-excited state with electronic excitation energy of around 1.21 eV. We revealed that such a structural phase transition is driven essentially by exciting two soft phonon modes.