基于小孔前壁一次吸收的激光深熔焊接能量耦合机制及热源模型研究

The laser deep-penetration welding technology is one of the commanding heights of the advanced manufacturing technology, and has garnered extensive attention in defense weapon, aerospace, vehicle manufacturing and other industries. Developing laser deep-penetration welding technology confirms with the national strategic development. The laser energy coupling in the keyhole is the key of the laser deep-penetration welding physical process, and plays an important role in the formation of welding defects. Recently, there are shortage of fully understanding about the laser energy coupling in the keyhole. The understanding and optimization of the laser deep-penetration welding process are thus restricted. In this project, the characteristics of the keyhole front wall and its laser energy absortion are studied in theory and experiment. The comprehensive understanding of the laser energy coupling mechanism in keyhole is expected to be achieved. The aims of the project are: to study the three-dimensional morphology of keyhole and the influence factors of the keyhole wall morphology, the transfer behavior of laser beam in keyhole, the laser energy absorption model in the keyhole wall, the space distribution of evaporation recoil pressure, the time-varying characteristics of keyhole and molten pool, etc. To reveal the interaction mechanism between the laser beam and the keyhole wall, establish the laser deep-penetration welding heat source model based on the first absorption of keyhole front wall. The research results can establish the theoretical foundation for the development and application of the laser deep-penetration welding technology in our country.

激光深熔焊接技术是国际先进制造技术的制高点之一，在国防武器、航空航天、轨道交通等领域获得了广泛的关注。研究和发展激光深熔焊接技术符合国家的战略发展决策。小孔内的激光能量耦合是激光深熔焊接物理过程的关键环节，对焊接缺陷的产生起着重要作用。目前对小孔内激光能量耦合机制的认识不足，故而制约了对激光深熔焊接过程的理解和优化。本项目针对小孔前壁形貌及前壁的激光能量吸收展开深入的理论和实验研究，有望全面认识孔内激光能量耦合机制。本项目将深入研究激光深熔焊接小孔三维形貌和孔壁介观形貌的影响因素、孔内激光能量传输行为、孔壁激光能量吸收模型、蒸发反冲压力空间分布规律、小孔/熔池的时变特征等，揭示深熔焊接中激光束与孔壁的相互作用机理，建立基于前壁一次吸收的激光焊接热源模型，为激光深熔焊接技术在我国的进一步发展和应用奠定理论基础。

激光深熔焊接技术是国际先进制造技术的制高点之一，在国防武器、航空航天、轨道交通 等领域获得了广泛的关注。研究和发展激光深熔焊接技术符合国家的战略发展决策。小孔内的激光能量耦合是激光深熔焊接物理过程的关键环节，对焊接缺陷的产生起着重要作用。目前对小孔内激光能量耦合机制的认识不足，故而制约了对激光深熔焊接过程的理解和优化。项目申请人针对“深熔小孔前壁的介观形貌及其影响因素；激光束在小孔前壁上的吸收行为及孔内激光能量耦合机制；深熔小孔的动态特性行为及小孔的失稳机制；激光深熔焊接线能量特征及焊接热源模型的建立”这四个方面开展了系统的理论和实验研究工作。揭示激光深熔焊接小孔三维形貌的形成规律及影响因素、熔池凝固时域内表面介观形貌的演化、羽辉和等离子体对能量耦合的影响、光束在孔内的传输行为、孔壁激光能量吸收理论模型、前壁蒸发反冲压力的特征、小孔/熔池的时变特征等。初步认识孔内激光能量转化与焊接过程的对应关系；建立了小孔前壁介观形貌↔前壁对入射激光的吸收模型↔孔内激光能量耦合规律↔小孔前壁激光致蒸发反冲压力↔小孔时变特征之间的对应关系。阐明了飞溅、驼峰、焊缝表面成形差、小孔型气孔等焊接缺陷的主要影响因素，为激光深熔焊接制造过程质量控制奠定理论基础。构建了基于小孔前壁一次吸收的激光深熔焊接热源模型，准确地预测了焊接熔深，并进一步开发了熔宽和焊缝横截面形状计算模型，研究成果对丰富和发展激光深熔焊接理论和技术体系具有重要意义。本项目初步构建了激光深熔焊接热源模型以及激光束与小孔壁相互作用的理论框架，可为激光深熔焊接技术的优化、及该技术在我国的进一步发展和应用奠定基础。.已发表学术论文共25篇，其中SCI期刊检索文章17 篇，EI期刊检索论文6 篇；其它检索文章2 篇；获国家授权发明专利6 件；作会议口头报告6 人次（邀请报告3次）；培养已毕业硕士3 人，在读硕士生2 人，在读博士生2 人。