高温复合多层膜结构传感器的热机械可靠性

摘要

This paper mainly discussed the thermal mechanical reliability of the thin film thermocouple transducer applied composite multilayer thin-film structure under high or low temperature impact .The elastic-plastic model was built and analyzed by finite element simulation .And the complicated thermal stress and strain distribution of the interfacial lines were analyzed systemical -ly due to the large thermal expansion mismatch between adjacent films .In order to find out the fatal reliability issues on the thin film transducer qualitatively , the stress concentration area and regional distribution of strain accumulation were analyzed .Compared with the 400℃temperature load, the von Mises stress of the thin-film thermocouple temperature transducer under limited temperature 1 200℃increased more than 50%.When the thermal loads acted repeatedly , the structure of the multilayer films was badly dam-aged especially on transition layer , and the internal plastic deformation of adjacent films increased severe and turned the interfaces associated with the work layer into weaker reliability areas .%文中主要讨论了应用于薄膜热电偶温度传感器的复合多层膜结构在高低温热冲击条件下的热机械可靠性。采用基于FEM有限元仿真方法的弹塑性模型，系统分析了由多层膜材料热失配导致的界面复杂热应力应变分布规律。定性给出了可能导致致命可靠性问题的应力集中区域及应变积累区域分布。与400℃温度载荷相比，薄膜热电偶温度传感器在1200℃极限温度下最大范密歇斯应力增大50％以上。同时当温度载荷反复作用时，不仅多层膜结构的过渡层受到严重破坏而且相邻界面的内部塑性形变越发严重，使与工作层相关连的界面成为可靠性薄弱区域。