李文兰, James C. M. Li. 晶粒大小对断裂韧性的影响[J]. 武汉大学学报 ( 信息科学版), 1991, 16(2): 79-91.
引用本文: 李文兰, James C. M. Li. 晶粒大小对断裂韧性的影响[J]. 武汉大学学报 ( 信息科学版), 1991, 16(2): 79-91.
Li Wenlan, James C. M. Li. The Effect Of Grain Size On Fracture Toughness[J]. Geomatics and Information Science of Wuhan University, 1991, 16(2): 79-91.
Citation: Li Wenlan, James C. M. Li. The Effect Of Grain Size On Fracture Toughness[J]. Geomatics and Information Science of Wuhan University, 1991, 16(2): 79-91.

晶粒大小对断裂韧性的影响

The Effect Of Grain Size On Fracture Toughness

  • 摘要: 本文研究位错群从一个Ⅱ型或Ⅲ型加载的半无限裂纹进行发射和被一个可穿透障碍(晶粒间界)或许多这种等间距障碍阻塞或锁闭的问题。得到了裂纹顶端和一个障碍之间位错连续分布用的解析解。通过计算机模拟,研究了多重障碍的情况。其结果可用来推断晶粒大小对断裂韧性的影响。对于上述加载的应力强度因子,发现断裂韧性随晶粒大小的增加而增加。利用一个幂律关系(其幂指数在0~1.5之间变动)具体取值决定于位错运动的晶格摩擦力与晶粒间界强度之比,连同关联晶粒与大小断裂应力的Petch方程。本文给出了晶粒大小与裂纹扩展用的临界应力强度因子之间的关系。

     

    Abstract: The Problem of dislocations emitted from a semi-infinite crack in mode Ⅱ or Ⅲ loading and blocked by a penetrable barrier(grain boundary),or many such epually spaced barriers,is studied.Analytical solutions for the continuous distribution of dislocations between the crack tip and a barrier is obtained.The case of multiple barriers is studied by computer simulation.The results are used to understand the effect of grain size on fracture toughness.For the same applied stress intensity factor,the toughness is found to increase with increasing grain size.By using a power-law relation,the exponent varies between 0 and 1.5 depending on the ratio of the lattice friction for dislocation motion to the grain-boundary strength.Together with the Petch relation for the dependence of grain size on fracture stress,a relation is suggested between the grain size and the critical stress intensity factor for crack propagation.

     

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