Ou Xuelian, Shen Yanxin, Yang Yue, You Zhenjiang, Wang Peng, Yang Yexin, Tian Xiaofeng
The College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu 610059, China.
Center for Sustainable Energy and Resources, Edith Cowan University, Joondalup, WA 6027, Australia.
Materials (Basel). 2023 Jun 27;16(13):4618. doi: 10.3390/ma16134618.
U-Mo alloys were considered to be the most promising candidates for high-density nuclear fuel. The uniaxial tensile behavior of nanocrystalline U-10Mo alloys with average grain sizes of 8-23 nm was systematically studied by molecular dynamics (MD) simulation, mainly focusing on the influence of average grain size on the mechanical properties and deformation mechanisms. The results show that Young's modulus, yield strength and ultimate tensile strength follow as average grain size increases. During the deformation process, localized phase transitions were observed in samples. Grain boundary sliding and grain rotation, as well as twinning, dominated the deformation in the smaller and larger grain sizes samples, respectively. Increased grain size led to greater localized shear deformation, resulting in greater stress drop. Additionally, we elucidated the effects of temperature and strain rate on tensile behavior and found that lower temperatures and higher strain rates not only facilitated the twinning tendency but also favored the occurrence of phase transitions in samples. Results from this research could provide guidance for the design and optimization of U-10Mo alloys materials.
铀钼合金被认为是高密度核燃料最有前景的候选材料。通过分子动力学（MD）模拟系统研究了平均晶粒尺寸为8 - 23纳米的纳米晶U - 10Mo合金的单轴拉伸行为，主要关注平均晶粒尺寸对力学性能和变形机制的影响。结果表明，随着平均晶粒尺寸的增加，杨氏模量、屈服强度和极限抗拉强度随之变化。在变形过程中，观察到样品中存在局部相变。晶界滑动和晶粒旋转以及孪晶分别在较小和较大晶粒尺寸的样品变形中起主导作用。晶粒尺寸的增加导致更大的局部剪切变形，从而导致更大的应力降。此外，我们阐明了温度和应变速率对拉伸行为的影响，发现较低温度和较高应变速率不仅促进了孪晶倾向，而且有利于样品中相变的发生。本研究结果可为U - 10Mo合金材料的设计和优化提供指导。
