含氢原子缺陷晶界的剪切行为

发布时间：2018-09-01 07:45

【摘要】：针对4个α-Fe对称倾斜晶界,采用分子静力学考察了4个晶界中H原子偏析能的分布特征,并采用分子动力学方法研究了晶界内植入不同数量H原子对其在室温条件下剪切行为的影响.H原子通过随机方式植入界面内,利用植入H原子数量与晶界面积的比值来定义H原子面密度ρ.在含H原子晶界剪切行为分析过程中,重点考察了在不同H原子密度ρ下,4个晶界的初始塑性临界应力和晶界迁移位移的变化趋势以及4个晶界在加载过程中的微观变形机理.研究表明:晶界内的H原子偏析能明显偏低,4个晶界附近的H原子会自发向晶界内偏析;随着植入H原子数量的逐渐增多,晶界的初始塑性临界应力和后续变形阶段应力均会降低.晶界内植入H原子会从本质上改变晶界的微观变形机理,进而影响晶界在外载荷条件下的迁移属性.与不含H原子晶界的变形机理对比发现,加载过程中晶界的微结构会发生剧烈的演化,H原子的扩散和团簇化效应会导致晶界内出现纳米孔缺陷.
[Abstract]:For four 伪 -Fe symmetric inclined grain boundaries, the distribution characteristics of segregation energy of H atoms in the four grain boundaries were investigated by molecular statics. The effects of different number of H atoms implanted in grain boundaries on shear behavior at room temperature were studied by molecular dynamics method. H atoms were implanted into the interface in a random manner. The density 蟻 of H atom is defined by the ratio of the number of implanted H atoms to the grain boundary area. During the analysis of the shear behavior of the grain boundaries containing H atoms, the variation trend of the initial plastic critical stress and the grain boundary migration displacement of the four grain boundaries at different H atom densities 蟻 and the microscopic deformation mechanism of the four grain boundaries during loading were investigated. The results show that the segregation energy of H atoms in grain boundaries is obviously low, and the H atoms near the four grain boundaries will spontaneously segregate into the grain boundaries, and with the increasing of the number of H atoms implanted, The initial plastic critical stress at grain boundary and the stress at subsequent deformation stage will decrease. The implantation of H atoms in grain boundaries will change the microscopic deformation mechanism of grain boundaries in essence, and then affect the migration properties of grain boundaries under external loads. Compared with the deformation mechanism of the grain boundary without H atom, it is found that the microstructure of the grain boundary will undergo intense evolution during loading. The diffusion and cluster effect of H atoms will lead to the formation of nano-pore defects in the grain boundary.
【作者单位】：西安交通大学航天航空学院机械结构强度与振动国家重点实验室/陕西省航天结构振动控制工程实验室;
【基金】：国家自然科学基金资助项目(11502191,11372238,11632014)
【分类号】：TG111.2

【相似文献】