(中南大学 粉末冶金研究院，长沙 410083)
摘 要: 本文采用分子动力学模拟方法研究了Nb含量对锆铌合金拉伸变形行为的影响。结果表明：不同Nb含量的ZrNb合金在单轴拉伸变形中所表现的相变行为和纯锆相似，外加载荷会诱发合金遵循Pitsch-Schrader(PS)位向关系的密排六方结构(HCP)到体心立方结构(BCC)的相变，随后BCC相沿贝恩路径(Bain path)转化为FCC相。通过计算不同ZrNb合金体系形成基面层错的能量变化，发现随着Nb含量的增加，形成基面层错的能垒增加，即Nb的加入不利于ZrNb合金中产生基面层错。随着Nb含量的提高，ZrNb合金的应力-应变曲线斜率有略微增加，弹性模量有所提高，但是合金体系的屈服强度逐渐降低。本研究将有助于更好地理解锆铌合金的变形机理。
关键字: 锆铌合金；变形机制；分子动力学模拟
（State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:In this paper, the molecular dynamics simulation was used to study the influence of niobium content on the tensile deformation behavior of ZrNb alloys. The results show that the phase transformation behavior of ZrNb alloys with different Nb contents during uniaxial tensile deformation is similar to that of pure zirconium. Externally applied loading induces the hexagonal close-packed (HCP) to body-centered cubic (BCC) phase transition following the Pitsch-Schrader (PS) orientation relationship (OR). Then, the face-centered cubic (FCC) structure transforms from the BCC phase in the Bain path. By calculating the basal stacking fault energy of different ZrNb alloy systems, it is found that the energy barrier for forming basal stacking faults increases with the increasing Nb content. Therefore, it is more difficult for the generation of basal stacking faults in ZrNb alloys with a higher Nb content. With the increase of Nb content, the slope of the ZrNb alloys’ stress-strain curve increases slightly and thus the elastic modulus increases, while the yield strength of the alloy gradually decrease. This study may provide a better understanding of the deformation mechanism of zirconium-niobium alloys.
Key words: ZrNb alloy; deformation mechanism; molecular dynamics simulation
