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为了探索用压痕法确定晶体学蠕变应力指数的可行性,采用晶体塑性理论模型对不同取向镍基单晶合金压痕蠕变行为进行了有限元模拟。研究表明,晶体学对称性会导致压痕表面应力呈现特定的对称性;晶体取向对压痕蠕变深度及其扩展速率具有显著的影响。通过开展不同载荷下的压痕蠕变模拟,获得相应的稳态压痕深度扩展速率,再通过线性回归的方法可有效获得晶体学蠕变应力指数。本文提出的确定蠕变应力指数的方法不受晶体取向的影响,有望应用于各向异性高温合金蠕变性能评估。
In order to explore the feasibility of using indentation method to determine the creep stress index of crystallography, the plastic-plastic theory model was used to simulate the indentation creep behavior of different orientation Ni-based single crystal alloys. The results show that the crystallographic symmetry leads to a certain symmetry of the indentation surface stress. The crystal orientation has a significant influence on the indentation creep depth and its propagation rate. By carrying out indentation creep simulation under different loads, the corresponding steady state indentation depth expansion rate is obtained, and then the crystallographic creep stress exponent can be obtained by the linear regression method. The method proposed in this paper to determine the creep stress index is not affected by the crystal orientation and is expected to be applied to the creep property evaluation of anisotropic superalloy.