晶体孪晶
材料科学
层错能
退火(玻璃)
晶界
变形机理
复合材料
透射电子显微镜
动态再结晶
表层
图层(电子)
微观结构
纳米技术
热加工
作者
Baochen Li,Hongguang Liu,Zhang Jun,Binbin Xu,Wanhua Zhao
标识
DOI:10.1016/j.ijmachtools.2023.104074
摘要
Microstructural features are an important factor in the evaluation of machined surface integrity. In particular, twins and twin boundaries have a significant impact on the physical and mechanical properties of components. This study investigates twin boundary evolution mechanisms in the machined surface during orthogonal cutting of oxygen-free-high-conductivity copper with cutting speeds ranging from 125 m/min to 2000 m/min. Pertinent features including twin boundaries, grain morphologies, textures, etc. Are characterized by electron backscattered diffraction and transmission electron microscope. The results show that the machined surface is divided into the refined layer, the deformed layer, and the matrix. An abnormal gradient distribution of a 60°<111> twin boundary is discovered for the first time. Specifically, the annealing twins mostly diminish in the deformed layer and regenerate in the refined layer. In the refined layer, a temperature-dominated process of twin formation and dynamic recrystallization occur. In the deformed layer, the resolved shear stress along the twin system is calculated through a novel approach, which reveals the stress-induced detwinning mechanism. The results of this research are beneficial for understanding both the deformation mechanism of medium stacking fault energy face-centered cubic metal under extreme loading conditions and the underlying effects of twins on the mechanical properties of machined surface.
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