文 献 综 述
摘 要：
近年来，单晶金属滑移阻力的尺度效应受到广泛关注。扫描电子显微镜原位测试证明样品尺寸越小，位错滑移阻力越高。这主要与位错饥饿以及单臂位错截断等微观模型有关。目前，多数测试局限于10微米以下样品，因此学术界对位错滑移阻力的尺度效应如何过渡至传统块体单晶金属尚不清楚，其主要原因是缺少10微米以上至毫米级单晶样品的力学测试。
尺寸尺度效应可以定义为由于材料内部特征、结构的尺寸或样品的整体物理尺寸的变化而引起的材料性能（机械、电气、光学或磁性）的变化。对于金属来说，与金属内部长度尺寸变化有关的尺寸尺度效应很容易观察到，并且常常被用于工业用途。例如，众所周知，金属的屈服强度可以通过细化晶粒尺寸来证明的，其中屈服强度与平均晶粒直径的平方根成反比，这种关系通常适用于尺寸从毫米到几十纳米的晶粒。相比之下，仅仅由于样品的物理几何结构引起的材料力学行为的变化在很大程度上被忽略了[1]。
本课题将系统开展数十微米至毫米尺度的单晶铜金属的力学测试，定量确定单晶金属位错滑移不同阶段的临界分切应力和临界应变的尺度效应。
关键词：毫米级单晶样品；单晶铜金属；尺度效应；块体单晶金属。
Abstract：
In recent years, the scale effect of slip resistance of single crystal metals has been widely concerned. Scanning electron microscopy (SEM) in-situ test shows that the smaller the sample size is, the higher the dislocation slip resistance is. This is mainly related to the micro models of dislocation starvation and single arm dislocation truncation. At present, most of the tests are limited to the samples below 10 mu; m, so it is not clear how the scale effect of dislocation resistance transition to the traditional bulk single crystal metal in the academic community. The main reason is the lack of mechanical tests for single crystal samples above 10 mu;m to mm.
The size scale effect can be defined as the change of material properties (mechanical, electrical, optical or magnetic) caused by the change of the internal characteristics of the material, the size of the structure or the overall physical size of the sample. For metal, the size scale effect related to the change of internal length and size of metal is easy to observe, and is often used for industrial purposes. For example, it is well known that the yield strength of a metal can be demonstrated by refining the grain size, where the yield strength is inversely proportional to the square root of the average grain diameter, and this relationship is generally applicable to grains with sizes ranging from millimeters to tens of nanometers. In contrast, the change of mechanical behavior of materials caused only by the physical geometry of the sample is largely ignored.
In this project, we will systematically carry out mechanical tests of single crystal copper metal at the scale of tens of microns to millimeters, and quantitatively determine the scale effect of critical shear stress and critical strain at different stages of dislocation slip of single crystal metal.
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