共晶基复相陶瓷中缺陷的稳定性分析

发布时间：2018-03-15 20:16

本文选题：夹杂　切入点：缺陷　出处：《机械强度》2017年06期 　论文类型：期刊论文

【摘要】：共晶基复相陶瓷材料中,不同相间的热膨胀系数的差异产生的缺陷是降低材料强度的重要因素。基于等效夹杂理论和相互作用直推估计法,计算得到颗粒周围缺陷在热残余应力和外载应力作用下的应力强度因子,研究了缺陷的扩展稳定性,并分析了颗粒刚度、形状、含量等参数对扩展稳定性的影响规律。结果显示:扁平形的颗粒环向最容易产生热裂纹;刚性颗粒能够在一定程度上降低外载应力在基体中平均作用效果,且长椭球状刚性颗粒的降低程度要大于扁椭球颗粒,因此有利于缺陷的稳定,柔性颗粒作用相反;当缺陷扩展量很小,应力强度因子主要受残余应力控制,缺陷扩展量较大时,应力强度因子主要受基体平均应力控制,长椭球形柔性颗粒有利于提高材料强度。
[Abstract]:In eutectic multiphase ceramic materials, the defects caused by the difference of thermal expansion coefficient between different phases are important factors to reduce the strength of the materials. The stress intensity factors of the defects around the particles under the action of thermal residual stress and external stress are calculated. The propagation stability of the defects is studied, and the stiffness and shape of the particles are analyzed. The effect of the content and other parameters on the propagation stability. The results show that the flat particles are most likely to produce hot cracks in the circumferential direction, and the rigid particles can reduce the average effect of the external stress in the matrix to a certain extent. And the reduction of long ellipsoid rigid particles is greater than that of flat ellipsoid particles, so it is advantageous to the stability of defects, and the effect of flexible particles is opposite, when the defect propagation is very small, the stress intensity factor is mainly controlled by residual stress, and the defect expansion is larger. The stress intensity factor is mainly controlled by the average stress of the matrix, and the long ellipsoidal flexible particles can improve the strength of the material.
【作者单位】：军械工程学院车辆与电气工程系;军械工程学院基础部;
【基金】：国家自然科学基金项目(11272355)资助~~
【分类号】：TQ174.1

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