SINA - Sensor integration in aluminum die casting

生产金属零件最重要的技术是铸造。金属零件往往采用承重功能，同时承受较高的热应力和机械应力。他们的失败是一个巨大的安全风险。关于这一点，用传感器监测它们的功能似乎是适当的。理想情况下，传感器应该直接嵌入金属中。研究现状表明，在金属部件中集成传感功能的重要性。到目前为止，由于铸件温度高和冷却过程中的热应力，在金属中集成传感器元件势必会失败。传感器元件在埋设过程中损坏或断裂。该项目首次研究了传感器和铸造技术的创新结合。其目的是使金属零件在铸造时就具备传感器功能。具体来说，研究了压阻式应变传感器在铝压铸件中的集成。研究了几种材料组合和工艺流程，以满足极高温度（几百℃）和高压的边界条件。进行了数值模拟，对传感器元件进行了处理、嵌入和分析。研究了损伤机理。开发了嵌入式传感器元件电气互连的安装技术。嵌入式传感器在材料中充当异物，可能降低机械强度。该效应通过数值模拟进行了理论研究，并通过显微镜、显微照片、拉伸和弯曲试验以及动态疲劳试验进行了实验。为了确定传感器在金属中的位置，提出了定位的概念。利用有限元分析，开发了热载荷和机械载荷模式，并用于改进传感器元件的布局。

SINA - Sensor integration in aluminum die casting The most important technology to produce metal parts is casting. Metal parts often adopt load-bearing function and are subject to high thermal and mechanical stress at the same time. Their failure is a mayor security risk. Regarding this it seems appropriate to monitor their function by sensors. Ideally, the sensor should be embedded directly in the metal. The state of research shows the high importance of integrating sensing function in metal parts. Up to now, integrating sensor elements in metals during casting was bound to fail due to the high temperatures of casting and due to the thermomechanic stress during cooling down. The sensor elements were harmed or broken during embedding. The requested project investigates for the first time an innovative combination of sensor and casting technology. The aim is to equip metal parts with sensor function already while they are casted. Specifically, the integration of piezoresistive strain sensors in aluminum die casting is investigated. Several material combinations and technological process flows are investigated to meet the boundary conditions of very high temperature (several hundred °C) and high pressure. Numerical simulations are performed, sensor elements are processed, embedded and analyzed. The damage mechanisms are investigated. Mounting technologies for the electrical interconnection of the embedded sensor elements are developed. The embedded sensor acts as a foreign body in the material which may downgrade the mechanical strength. This effect is investigated theoretically using numeric simulation and experimentally using microscopy, micrographs, pull- and bending-test, and dynamic fatigue tests. In order to get a definite positioning of the sensors in the metal, concepts for positioning are developed. Using Finite Element Analysis, thermal and mechanical load patterns are developed and used to improve the layout of the sensor elements.