晶粒尺寸对纳晶双峰材料断裂韧性的影响

发布时间：2018-02-24 18:07

本文关键词： 纳晶双峰材料位错粘聚力断裂韧性晶粒尺寸　出处：《稀有金属材料与工程》2015年11期 　论文类型：期刊论文

【摘要】：为了描述由纳晶基体和粗晶颗粒组成的纳晶双峰材料的断裂韧性,通过建立一个粘聚力模型来研究纳晶双峰材料的临界应力强度因子K_(IC)(表征材料断裂韧性)。考虑到纳晶双峰材料的一个典型情况:裂纹位于2个纳晶颗粒的交界面处,裂纹尖端与粗晶粒的晶界相交,假设粘聚区的尺寸等于纳晶颗粒的尺寸d。裂纹的钝化和扩展过程受位错和粘聚力的共同影响,刃型位错是从粘聚力裂纹的尖端发射,该过程对裂纹产生屏蔽效应。模型计算结果显示:当粗晶颗粒尺寸D确定时,K_(IC)随着纳晶材料晶粒尺寸d的增大而增大;当纳晶材料晶粒尺寸d确定时,K_(IC)随着粗晶材料晶粒尺寸D的增大而增大;相对于纳晶颗粒的尺寸,断裂韧性对粗晶晶粒的尺寸更加敏感。
[Abstract]:In order to describe the fracture toughness of nanocrystalline bimodal material composed of nanocrystalline matrix and coarse grain, A cohesive force model is established to study the critical stress intensity factor (KSP) of nanocrystalline bimodal materials (characterizing the fracture toughness of nanocrystalline bimodal materials). Considering a typical case of nanocrystalline bimodal materials, the crack is located at the interface of two nanocrystalline particles. The crack tip intersects with the grain boundary of coarse grain, assuming that the size of the agglutination zone is equal to that of nanocrystalline grain D. the process of crack passivation and propagation is affected by dislocation and cohesion, and the edge dislocation is emitted from the tip of cohesive crack. The model calculation results show that when the coarse grain size D is determined, the K / C ICs increase with the increase of the nanocrystalline grain size d. When the grain size d of nanocrystalline material is determined, the K / C) increases with the increase of coarse grain size D, and the fracture toughness is more sensitive to the size of coarse grain than that of nanocrystalline particle.
【作者单位】：华北电力大学;
【基金】：国家自然科学基金(51301069)
【分类号】：TG146.21

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