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

发展了一种系统的方法来阐明和表征韧性单晶的基本微力学断裂机制。为了消除晶界缺陷和提高高温性能，以单晶形式生产的整个结构和电子元件越来越多。确定了导致裂纹扩展的静止裂纹尖端场的特征。研究了重复加载循环对静止裂纹应力场和变形场的影响。在扩展裂纹附近的应力场和变形场被确定来创建一个在延性单晶中如何发生破坏的整体图像。实验程序采用云纹显微镜对单晶弹塑性公式进行了一级和二阶渐近分析，并进行了理论分析。

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.