GOALI/Collaborative Research: Fundamental Research on Impact Welding of Aluminum and Steel

这个学术与工业联络（GOALI）合作研究奖的资助机会支持对新兴焊接技术的基础研究-冲击焊接-连接材料组合，否则很难连接。研究将集中在铝-钢焊接，因为有不同的和重要的商业需求，在加入这些金属。 这两种基础金属都有很好的特性，开发坚固的铝-钢接头可以减少汽车的质量。更轻的汽车使用更少的燃料，向大气排放更少的碳。研究成果将使这项技术在汽车、航空航天和医疗器械等重要行业得到更广泛的应用。 传统的焊接工艺会熔化待连接的两种金属，并且熔融混合会导致脆性的金属间化合物，使得接头不适合于大多数结构应用。 冲击焊接可以是坚固和坚韧的，并且通过两个金属表面之间的高速（通常200-700 m/s）倾斜碰撞在固态下产生。本研究的目的是：1）了解飞板的厚度（因此其总动能）如何影响所形成的界面的结构，2）了解在冲击焊接过程中的应变，温度和界面形态的实时演变和3）将变形历史与焊缝的最终结构和性能联系起来。 独特的工具用于研究25微米至25毫米厚度的飞片的铝-钢冲击。激光冲击焊接和爆炸焊接分别用于最薄和最厚的飞片，而蒸发箔致动器焊接将用于加速几个中间厚度的飞片。 光子多普勒测速仪将能够详细测量碰撞速度和角度。 基于光滑粒子流体动力学和任意拉格朗日-欧拉方法的有限元模型将被开发用于这些问题。它们的有效性将通过焊接结构的金相检查和这些模拟的比较进行测试。这些模型将用于了解材料应变、温度和结构的复杂动态发展，以及各种长度尺度。

This Grant Opportunity for Academic Liaison with Industry (GOALI) collaborative research award supports fundamental research on an emerging welding technology - impact welding - to join material combinations that are otherwise difficult to join. Research will focus on aluminum-steel welds because there are diverse and important commercial needs in joining these metals. Both base metals are well characterized and the development of robust aluminum-steel unions can reduce automobile mass. Lighter cars use less fuel and emit less carbon to the atmosphere. Research results will enable wider application of this technology in important industries including automotive, aerospace, and medical devices. Traditional welding processes melt both metals to be joined and the molten mixing can result in brittle intermetallic compounds, rendering the joints unsuitable for most structural applications. Impact welds can be strong and tough and are created in the solid state by a high-speed (typically 200-700 m/s) oblique collision between two metal surfaces. The objectives of this research are: 1) to understand how the thickness of the flyer plate (and therefore its total kinetic energy) affects the structure of the interface that is formed, 2) to understand the real-time evolution of strain, temperature and morphology of the interface during the impact welding process and 3) relate the deformation history to the final structure and properties of the weld. Unique tools are used to study aluminum-steel impacts from flyer thicknesses of 25 µm to 25 mm. Laser impact welding and explosive welding are used for the thinnest and thickest flyers, respectively, while vaporizing foil actuator welding will be used to accelerate flyers of several intermediate thicknesses. Photonic Doppler velocimetry will enable detailed measurements of collision speed and angle. Finite element models based on Smoothed Particle Hydrodynamics and Arbitrary Lagrangian-Eulerian methods will be developed for these problems. Their validity will be tested by metallographic examination of welded structures and comparison of these to simulation. These models will be used to understand the complex dynamic development of material strains, temperatures and structures and on a wide range of length scales.