激光选区熔化Ti-6Al-4V（TC4）合金兼具传统铸造TC4合金的优点，且在致密度、屈服强度、抗拉强度等方面有明显提高。然而激光选区熔化技术由于较大温度梯度极易在材料内部积聚残余应力，引起构件变形、裂纹及层间分离，对构件的正常功能和结构完整性造成破坏，因此系统研究激光选区熔化TC4合金不同尺度残余应力分布及其对材料力学性能的影响至关重要。本项目拟对该材料细观乃至微纳观尺度下的力学性能和残余应力进行实验研究，分析不同尺度下残余应力对材料力学性能的影响。具体内容包括：基于电子束云纹法结合扫描电子显微镜原位拉伸实验，研究材料在微纳观尺度下的力学行为；利用XRD技术研究材料的细微观残余应力，应用纳米压痕法和电子束云纹法研究材料的微纳观残余应力；揭示残余应力形成机理及其对不同尺度下材料力学性能的影响机制，为建立激光选区熔化TC4合金的多尺度力学模型提供有效的实验依据并指导工程应。

Selective Laser Melting of Ti-6Al-4V(TC4) alloy combines traditional advantages of TC4 alloy casting, and the density, yield strength, tensile strength, ect have improved obviously. However, selective laser melting technology easy to cause material internal accumulation of residual stress. Artifacts caused by deformation, cracks and separation between the layers, damage to the normal function of the component and structural integrity. So it is very important to systematically study different scale residual stress distribution and its effect on the mechanical behavior of materials of sselective laser melting of Ti-6Al-4V alloy. This project focuses on the experimental study mechanical properties and residual stress of this material in the micro and nano scale, analysis influence of residual stress on the mechanical behavior. The concrete content includes: in situ tensile experiment will be performed besed on electron beam moire method combining with scanning electron microscope (sem), study on the mechanical behavior of micro nano scale. Research fine micro residual stress of materials using XRD technology. Research micro nano residual stress of materials using nano indentation method and electron beam moire method. Reveal the formation mechanism of residual stress and its effect on the mechanical behavior of materials under different scales, It is to provide effective experimental basis and guide engineering for set up multi-scale mechanics model of selective laser melting TC4 alloy.