毫秒激光辐照单晶硅的晶体塑性有限元模拟
关键词 毫秒激光 单晶硅 损伤 晶体塑性 有限元
毕业论文设计说明书外文摘要
Title Simulation of single-crystal silicon irradiated by a millisecond laser using crystal plasticity FEM
Abstract
A three-dimensional calculation model is established based on the theory of heat conduction equation and crystal plasticity strain.On the basis of fully considering the anisotropy of single-crystal silicon material and the physical parameters changing with temperature.Using COMSOL finite element analysis software to simulate the distribution of transient temperature field and thermal stress field of single-crystal silicon irradiated by a long pulse laser.Comparing experiment with the results of numerical simulation of the damage on single-crystal silicon to further explain the generation mechanism of cleavage crack located in the single-crystal silicon surface.The results showed that the temperature in the center of the laser irradiation is the highest in the whole area.Along the axial and radial the temperature decreases gradually.The distribution of temperature mainly tends to material surface area within the laser spot and render the conical distribution.The temperature gradient between spot center and other areas increases with irradiation time, which caused the generation of thermal stress. The material will slip when the shear stress of twelve different slip systems exceed the yield strength of single-crystal silicon.And plastic slip first occurs in the location of the laser spot center along the z axis.The whole slip area appears bowl-shaped distribution when we considerate the interaction of all the types of slip systems.The overlap between different slips act as perpendicular cleavage cracks along the [110] and the direction.
Keywords millisecond laser single-crystal silicon damage crystal plasticity FEM
目 次
1 引言 1
1.1 研究背景与意义 1
1.2 激光与硅材料相互作用的研究现状 2
1.3 本文的主要研究工作 3
2 晶体塑性滑移的基本理论 4
2.1 晶体塑性理论基础 4
2.2 晶体塑性变形运动学 7
2.3 晶体塑性本构关系 10
2.4 单晶应变硬化规律 11
3 温度场的数值模拟与分析 13
3.1 温度场的有限元模型 13
3.2 温度场的计算结果与分析 15
3.3 本章小结 17
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