Abstract F riction-stir A ssisted S cribe T echnique (FAST) was used to join AZ31 magnesium alloy to Zn-coated steels including hot-dipped galvanized 590 and electroplated 270 steel with and without coating. The mechanical properties and performance of a FAST joint are governed by its underlying interfacial and microstructural characteristics, which in turn are determined by the FAST tool and process parameters. The FAST tool was utilized to create a different scribe engagement depth that can vary the extent of chemical intermixing and size of mechanical hooks. Microstructure and chemistry investigations on the weld interface were assessed using scanning electron microscopy and electron dispersive spectroscopy. Mechanical properties including lap shear tensile strength and micro and nano hardness at different interfacial regions were correlated to the local microstructures. A finite element-based modeling approach was developed to identify optimal interfacial characteristics that lead to a desired mechanical performance. The results of the computational model were compared to the experimental observations. A sensitivity analysis was conducted to study the variation in the mechanical response and failure modes of the joint with respect to the interfacial characteristics. Results indicate that interfacial characteristics including hook shape can have a significant impact on the joint strength and failure modes.

中文翻译：

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界面特性对使用 FAST 获得的镁钢接头的影响

摘要 采用摩擦搅拌辅助切割技术 (FAST) 将 AZ31 镁合金连接到镀锌钢，包括有涂层和无涂层的热浸镀锌 590 和电镀 270 钢。FAST 接头的机械性能和性能受其潜在界面和微观结构特征的控制，而这些特征又由 FAST 工具和工艺参数决定。FAST 工具用于创建不同的划线接合深度，可以改变化学混合的程度和机械钩的大小。使用扫描电子显微镜和电子色散光谱对焊缝界面的微观结构和化学研究进行了评估。包括搭接剪切拉伸强度和不同界面区域的微米和纳米硬度在内的机械性能与局部微观结构相关。开发了一种基于有限元的建模方法，以识别导致所需机械性能的最佳界面特性。将计算模型的结果与实验观察结果进行比较。进行敏感性分析以研究接头的机械响应和失效模式相对于界面特性的变化。结果表明，包括钩形在内的界面特性会对接头强度和失效模式产生重大影响。开发了一种基于有限元的建模方法来确定导致所需机械性能的最佳界面特性。将计算模型的结果与实验观察结果进行比较。进行敏感性分析以研究接头的机械响应和失效模式相对于界面特性的变化。结果表明，包括钩形在内的界面特性会对接头强度和失效模式产生重大影响。开发了一种基于有限元的建模方法来确定导致所需机械性能的最佳界面特性。将计算模型的结果与实验观察结果进行比较。进行敏感性分析以研究接头的机械响应和失效模式相对于界面特性的变化。结果表明，包括钩形在内的界面特性会对接头强度和失效模式产生重大影响。