铝合金与碳纤维增强树脂复合材料搅拌摩擦焊的界面结合机理及其对接头性能的影响

汽车、航空航天等领域的轻量化和结构功能复合化设计使得金属与碳纤维增强树脂复合材料（CFRP）的连接需求日益迫切。搅拌摩擦焊（FSW）由于热输入低、热力条件可控等特点，在金属/CFRP的焊接上表现出极大的优势。但目前金属/CFRP的FSW接头强度不高，对焊接界面结合机理与接头性能关键影响因素的认识有待深入。本项目拟采用FSW对碳纤维增强聚酰胺、聚丙烯两种典型热塑性CFRP与铝合金进行搭接焊。深入研究不同FSW和表面预处理工艺下接头界面的成键和结构、树脂降解和气泡分布特征等，分析被焊材料表面特性及焊接温度和压力对界面结合的影响，以及焊接过程中的树脂降解和气泡形成演化行为，阐明焊接界面结合机理及成键关键影响因素，揭示气泡产生与湮灭演化规律，建立界面特性、树脂降解、气泡和接头力学性能的关系模型，从而实现金属与CFRP高强度可控焊接，为其工业应用提供指导和依据。

It is becoming more and more urgent for the joining of metals and carbon fiber reinforced plastics (CFRPs) due to the requirement of lightweight and performance combination in automobile, aerospace fields etc. Friction stir welding (FSW) has great advantages in joining metals and CFRPs due to its low heat input and controllable heat and pressure conditions. However, the strength of metal/CFRP FSW joints is relatively low, and the joint interface bonding mechanism and the key influence factors of the joint properties are still unknown. This project intends to adopt FSW to lap weld aluminum alloy and CFRPs with two typical thermoplastic matrixes, polyamide and polypropylene. The interface bonding, microstructure, plastic decomposition and bubble distribution under different FSW parameters and surface pretreatment processes are deeply studied. The influence of surface characteristics of welded materials and the temperature and pressure on the interface bonding is analyzed. Also, the evolution of plastic decomposition and bubbles during FSW is investigated. Based on the research above, it is expected to clarify the joint interface formation mechanism and its key influencing factors, the rule of the formation and annihilation of bubbles, and the relationship between the interface characteristics, plastic decomposition, bubble and joint properties. As a result, the controllable preparation of high-strength joints will be realized. This study will provide an important guidance and basis for the industrial application of metal/CFRP joints.