锆合金中氢化物的结构和弹性性能:结合第一性原理计算和实验  

Structures and Elastic Properties of Hydrides in Zirconium Alloys: First-Principle Calculations and Experiments

作　　者：包张飞 李新意 张夫恩[1] 周虹伶 石明华 栾佰峰[1] Bao Zhangfei;Li Xinyi;Zhang Fuen;Zhou Hongling;Shi Minghua;Luan Baifeng(Chongqing Key Laboratory of Light Metal Science and Technology,International Joint Laboratory for Light Alloys(Ministry of Education),College of Materials Science and Engineering,Chongqing University,Chongqing 400044,China;Xi'an Western Energy Material Techno-logies Co.,Ltd,Xi'an 710299,China)

机构地区：[1]重庆大学材料科学与工程学院轻合金教育部国际联合实验室轻金属科学与技术重庆市重点实验室,重庆400044 [2]西安西部新锆科技股份有限公司,陕西西安710299

出　　处：《稀有金属材料与工程》2023年第2期426-432,共7页Rare Metal Materials and Engineering

基　　金：National Natural Science Foundation of China(U1867202,U20A20232);Fundamental Research Funds for the Central Universities(2020CDJDPT001);“111”Project(B16007)。

摘　　要：采用第一性原理计算和实验方法研究了α-Zr及其氢化物的结构和弹性性能。考虑到所有可能的H-原子构型,构建了不同相的氢化物模型。结果表明,γ、δ和ε氢化物的稳定结构分别为P4_(2)/mmc、P4_(2)/nnm和I4/mmm。计算结果表明,ε氢化物的生成焓最低,并提出了γ→δ→ε的相变顺序。与α-Zr相比,氢化物的c轴晶格常数变小,γ、δ和ε单位胞的膨胀体积分别为12.1%、14.8%和17.9%。3种氢化物的计算弹性模量(E)均低于α-Zr,但弹性各向异性均高于α-Zr。通过纳米压痕实验分析了α-Zr基体和δ氢化物的弹性性能,结果表明,α-Zr基体和δ氢化物的E分别为116.88和111.01 GPa。因此,在氢化物/基体界面的氢化物侧容易发生应力集中,氢化物容易成为裂纹源,导致锆合金发生脆性断裂。The structure and elastic properties of α-Zr and its hydrides were investigated by first-principle calculations and experimental methods. Considering all possible H-atom configurations, different phase models of hydrides were constructed. Results show that the stable structures of γ, δ and ε hydrides are P4_(2)/mmc, P4_(2)/nnm and I4/mmm, respectively. Calculation results suggest that ε hydride has the lowest formation enthalpy, and the phase transition sequence of γ → δ → ε is proposed. Compared with those of α-Zr, the c-axis lattice constants of hydrides become smaller, and the expansion volumes of γ, δ and ε unit cell are 12.1%, 14.8% and 17.9%, respectively. The calculated elastic modulus(E) of the three hydrides are lower than that of α-Zr, but their elastic anisotropy is higher than that of α-Zr. The elastic properties of α-Zr matrix and δ hydride were analyzed by nanoindentation experiment and the results show that E of the α-Zr matrix and δ hydride is 116.88 and 111.01 GPa, respectively. Therefore, the stress concentration is easy to occur on the hydride sides near the hydrides/matrix interface, so the hydrides are more likely to be the sources of crack and cause brittle fracture of zirconium alloys.

关 键 词：氢化物 第一性原理 相稳定性 力学性能 

分 类 号：TG146.414[一般工业技术—材料科学与工程]