红外探测器窗口异种材料焊接残余应力和变形分析

Residual Stress and Deformation Analysis of Differential Material Welding in the Window of an Infrared Detector

平行平板光学零件焊接变形产生弥散斑影响会聚光束成像质量。用有限元法分析红外探测器窗口异种材料焊接界面的应力分布,根据Suhir双材料界面的弯矩平衡微分方程计算窗口弯矩分布,研究焊料厚度、不同焊料和被焊材料热膨胀失配对窗口变形的影响。在正交试验优化焊接工艺过程中,用激光干涉法检测窗口变形,检测结果表明窗片顶面的仿真计算变形曲面与实测轮廓曲面一致。材料热失配和钎焊料弹塑性是引起窗口变形的主要原因。

The welding deformation of parallel plate optical parts produces defocused spots,which affect the imaging quality of the focused beam.In this study,a finite element analysis method was used to analyze the stress distribution of the welding interface of different materials in the window of an infrared detector.The bending moment was calculated based on the equilibrium differential equation of the Suhir theory of stresses as presented in bi-material strips.In addition,the effects of different solders,solder thicknesses,and thermal expansion mismatch on the deformation of the window were studied.In an orthogonal experiment to optimize the welding process,the deformation of the window was detected using laser interfer ometry.The simulated deformation of the top surface of the window agreed with the experimental results.Results also showed that the thermal mismatch of materials and elastic-plastic properties of the solders were the main causes of window deformation.