Fundamental Fracture Mechanisms in Ductile Single Crystals: A Combined Analytical and Experimental Study

发展了一种阐明和表征延性单晶中基本微观力学断裂机制的方法。单晶形式的整个结构和电子部件的生产越来越多，以消除晶界缺陷并提高高温性能。确定了导致裂纹扩展的稳态裂纹尖端场的特征。研究了重复加载循环对稳态裂纹应力场和变形场的影响。应力和变形场附近的一个不断增长的裂纹被确定，以创建一个整体的图片如何发生故障的韧性单晶。实验程序采用莫尔显微镜，而理论分析则采用单晶弹塑性理论的领先和二阶渐近分析。

A methodical approach to elucidate and characterize the fundamental micromechanical fracture mechanisms in ductile single crystals is developed. There is an increasing production of entire structural and electronic components in single crystal form to eliminate grain-boundary flaws and enhance high- temperature performance. The features of stationary crack tip field that lead to growth are identified. The effects of repeated loading cycles on stationary crack stress and deformation fields are investigated. The stress and deformation fields near a growing crack are determined to create an overall picture of how failure occurs in ductile single crystals. The experimental program uses the Moire Microscope while leading and second order asymptotic analysis of a single crystal elasto- plasticity formulation is developed for the theoretical analysis.