钽、铁、钨三种体心立方金属裂纹的多尺度模拟及韧脆性分析

发布时间：2018-03-28 02:36

  本文选题：多尺度准连续介质法　切入点：Ⅰ型裂纹　出处：《物理学报》2016年19期

【摘要】：采用多尺度准连续介质法计算模拟了钽、铁、钨三种体心立方(body-centered-cubic,BCC)金属的I型裂纹断裂过程.观察了加载过程中裂纹尖端区域原子的位错、孪晶等塑性变形现象,以及裂纹的脆性开裂和扩展现象.模拟结果表明,不同BCC金属材料的裂纹在相同的加载下有不同韧脆性表现.在一定变形范围内,钽裂纹主要表现出的是裂纹尖端附近区域原子的位错和形变孪晶等塑性变形现象;铁裂纹在变形过程中先后表现出了塑性变形和脆性扩展现象,与实验结果吻合;钨裂纹在变形过程中则主要变现出脆性扩展现象.计算了三种金属材料的广义层错能曲线,得到其不稳定层错能;并分别用两种不同的韧脆性准则,对三种材料断裂模型的韧脆性行为进行分析,计算分析结果与模拟结果一致,从而验证了模拟结果的正确性.
[Abstract]:The mode I crack fracture process of tantalum, iron and tungsten body-centered-cubic-BCCs has been simulated by means of multi-scale quasi-continuum method. The plastic deformation phenomena of dislocations and twins in the crack tip region have been observed during loading. The simulation results show that different BCC metallic materials exhibit different ductile brittleness under the same loading. Tantalum cracks mainly show plastic deformation phenomena such as dislocations and deformation twins of atoms near the crack tip, and iron cracks exhibit plastic deformation and brittle propagation in the process of deformation, which are consistent with the experimental results. In the process of deformation, the brittle propagation of tungsten cracks is mainly realized. The generalized stacking fault energy curves of three kinds of metallic materials are calculated, and the unstable stacking fault energies are obtained, and two different ductile brittleness criteria are used respectively. The ductile brittleness behavior of three fracture models is analyzed, and the calculated results are in agreement with the simulation results, which verifies the correctness of the simulation results.
【作者单位】： 复旦大学航空航天系;
【基金】：国家自然科学基金(批准号:11572090)资助的课题~~
【分类号】：O346.1
，

本文编号：1674409