EAGER: Feasibility Study of Hybrid Friction-Stir Riveting of Mg Alloys

EARLY概念探索性研究赠款（EAGER）赠款为开发一种新的搅拌摩擦铆接技术提供资金，用于连接难以焊接的材料，如镁和铝合金，以及异种金属。在这种方法中，实心铆钉被用作搅拌摩擦焊接头，用于连接两件材料，可以是板材或大块金属。旋转和挤压的联合作用将铆钉推入金属中。 达到预定深度后，动作停止，铆钉留在金属中，形成理想的机械连接。在接合界面处也产生了固体结合环。锁定机制，缺陷的形成，以及有影响力的物理属性和重要的强度措施之间的关系的关节将进行调查。通过与自冲铆接、电阻点焊等连接方法的直接对比，验证了该连接方法的有效性，为今后更大规模、更深入地研究和优化该连接方法奠定了基础。对包括基体金属和铆钉在内的材料的影响以及获得的设计和工艺变量的基本理解将为该技术的进一步发展提供关键信息。为质量检验建立了一种连接接头质量与接头易于测量的几何属性之间的关系，某些关键工艺参数，如铆接过程中的扭矩和推力曲线，可用作真实的时间质量控制的手段。本研究的最终目标是开发一种稳健、经济和工业化的连接工艺，使先进材料在钣金行业的使用达到节能减排的目的。

This EArly-concept Grants for Exploratory Research (EAGER) grant provides funding for the development of a new friction-stir riveting technique for joining hard-to-weld materials such as Mg and Al alloys, and dissimilar metals. In this method, a solid rivet is used as a friction-stir welding head for joining two pieces of materials which can be either sheets or bulk metals. An action of combined rotation and pressing pushes the rivet into the metals. After a predetermined depth is reached, the action stops and the rivet is left in the metals, forming a desirable mechanical joint. A solid bonding ring is also created at the faying interface. The locking mechanism, defect formation, and relationship between influential physical attributes and important strength measures of a joint will be investigated. A direct comparison between this and other joining methods such as self-piercing riveting and resistance spot welding will be conducted to validate this new joining method.The successful completion of this research will pave the way for a future proposal for a larger scale, in-depth study and optimization of this joining method. The basic understanding of the effects of materials including the base metal(s) and rivet, and design and process variables obtained will provide critical information for further development of this technique. A relationship linking the quality of a joint to easily measurable geometric attributes of the joint will be developed for quality inspection, and certain critical process parameters such as the profiles of torque and thrust during riveting may be used as a means for real time quality control. The ultimate goal of this research is to develop a robust, economical and industrial joining process to enable the use of advanced materials in sheet metal industry for energy saving and emission reduction.