目录1 绪论 (3)2 摘要 (3)3 材料介绍 (7)4 激光焊接技术 (7)4.1 同种镁合金的激光焊接 (7)4.2 镁合金与铝合金的激光焊接 (7)5 等离子弧焊技术 (8)5.1 同种镁合金的变极性等离子弧焊 (8)5.2 镁合金的变极性等离子弧缝焊 (8)6 低能耗激光诱导增强电弧复合焊接技术 (9)6.1 同种镁合金板材的焊接 (9)6.2 同种镁合金薄板的焊接 (9)6.3 异种镁合金板材的焊接 (10)6.4 镁合金与钢异种金属的焊接 (10)7活性焊接技术 (11)7.1镁合金活性焊接 (11)7.2镁合金活性焊丝填丝焊接 (11)8 熔化胶接焊焊接技术 (12)8.1镁合金等离子弧胶接焊 (12)8.2镁合金与铝合金的激光胶接焊 (13)9 镁合金与铝合金的扩散焊接技术 (13)10 镁合金焊接接头电弧喷涂防护技术 (14)11 镁合金焊接技术的应用及展望 (15)12 结论 (17)13 致谢 (18)14参考文献 (19)绪论近10年来，由于受到能源节约以及环境保护的巨大推动，镁合金及其焊接技术的发展比任何时期都快，从焊接方法、焊接材料到焊接设备等方面都不断有新的突破，为镁合金焊接生产向优质、高效、低成本的方向发展提供了前所未有的良好条件，并大大促进了镁合金的产业化进程。
镁合金由于其自身的物理化学特点，导致其焊接有很大困难，满意的焊接质量不易获得。
镁合金的结晶温度区大，易于产生热裂纹；镁的沸点低，温度进一步升高后，其蒸气压比在相同温度下的铝合金要高4-5倍，因而焊接时温度一旦过高，镁会气化，产生爆炸形成飞溅；镁对氧的亲和力大，其氧化物密度较大，而容易形成夹杂；镁在接近熔化温度时，能与空气中的氮强烈化合生成脆性的镁的氮化物，显著降低接头力学性能；因此，实现镁合金优质焊接是比较困难的，在焊接时容易产生裂纹、气孔、飞溅等缺陷。
但是由于工业的迫切需要，许多科学工作者做出了很大的努力，并取得了一些重要成果。
摘要随着工业技术的发展，对汽车、摩托车、飞机的性能要求越来越高，降低结构重量成为提高性能的重要措施。
镁及其镁合金具有比重轻，比强度高，重复利用性强等优点被誉为二十一世纪最有发展潜力的基础材料之一。
我国镁资源储备位居世界第一，同时也是界上最大的镁生产国和出口国。
日前我国已占全球镁生产能力的3／4，产量的1／2。
但镁合金应用开发严重滞后，80％以上作为初级原料低价出口，造成我国镁资源的极大浪费。
随着我国加入世贸组织以及国际产业结构的调整，发展镁合金产业正面临重大的历史机遇与挑战。
加快镁合金应用与产品制备核心技术的开发，将成为我国制造并抢占相关领域技术制高点，形成具有国际竞争力的新产业群体，并起到至关重要的作用。
材料的发展，离不开连接问题。
良好的连接是简化产品设计、降低产品成本的有效措施之一，连结技术的发展程度将直接影响镁合金的广泛应用。
镁合金焊接方向，国内外的研究主要集中在氩弧焊、激光束。
由于镁合金具有熔点低，导热率高，线膨胀系数高，表向张力小等特点，氩弧焊等传统的焊接技术在高技术制造领域所占的比重日趋减少。
而激光焊接具有速度高，接头质量好等优点，得到了实际应用，但激光焊接设备投资和维护的本高，能量利用率低(尤其对铝、镁等具有高反射率的材料)，焊接时对被焊工件的组对间隙及位置精度要求很高，广泛应用受到了很大的限制。
根据现有焊接工艺存在的优缺点，大连理工大学首次提出采用激光一电弧复合热源焊接镁合金工艺。
实验发现，新工艺不仅综合了氩弧焊和激光焊两种焊接工艺的优点，克服两者存在的不足，还能显著增大焊接熔深、提高焊接质量，是一种很有发展前途的焊接工艺。
本文对比分析镁合金氩弧焊、激光焊及激光一氩弧复合热源焊焊缝成犁、接头组织和力学性能，探索高效、优质的镁合金焊接工艺，为镁合金的广泛应用提供技术支撑。
关键词:镁合金铝合金激光焊等离子弧焊The abstractalong with industrial technology's development, to the automobile, the motorcycle, airplane's performance requirement is getting higher and higher, reduces the construction weight to become enhances the performance the important measure. The magnesium and the magnesium alloy have the proportion to be light, the specific tenacity is high, the reuse strong and so on merits are honored as most have one in the 21st century development potential foundation materials.our country magnesium resources reserve is situated the world first, simultaneously is also on the biggest magnesium producer country and the export State. The other day our country has occupied the global magnesium productivity 3/4, output 1/2. But the magnesium alloy application development serious lag, 80% above take the primary raw material low price export, creates our country magnesium resources the enormous waste. Joins World Trade Organization as well as the international industrial structure adjustment along with our country, the development magnesium alloy industry is facing the significant historic opportunity and the challenge. Speeds up the magnesium alloy application and the product preparation core technologies development, will become our country to make and to seize the related domain technology commanding point, forms has the international competitiveness new industrial groups, rises together simultaneously to the very important function. The material development, cannot leave the connection question. The good connection is simplifies the product design, to reduce one of product cost effective actions, links technical the degree of development the immediate influence magnesium alloy widespread application. The magnesium alloy welding direction, the domestic and foreign research mainly concentrate in the argon arc welding, the laser beam. Because the magnesium alloy has the melting point to be low, the thermal conductivity is high, the linear expansion coefficient is high, the table to the tensity small and so on characteristics, traditional and so on argon arc welding bonding techniques the proportion which occupies in the high-tech manufacture domain reduces day by day. But the laser welding has the speed to be high, attachment quality good and so on merits, obtained the practical application, but the laser welding equipment investment and the maintenance are originally high, the energy use factor low (to aluminum, magnesium and so on has high index of reflection material especially), when welding to is welded the work piece the group is very high to the gap and the position accuracy requirement, the widespread application has received the very big limit. According to the existing welding process existence's good and bad points, the Dalian University of Science and Technology proposed for the first time uses a laser electric arc compound heat source welding magnesium alloy craft. The experiment discovered that the new craft not only synthesized the argon arc welding and the laser welds two kind of welding processes the merit, overcomes both existence the insufficiency, but can also obviously increase the welding depth of fusion, the enhancement welding quality, is one kind has the career development welding process very much. this article contrastive analysis magnesium alloy argon arc welding, the laser weld and a laser argon arc compound heat source weld welded joint Cheng Li, the attachmentorganization and the mechanical properties, the exploration highly effective, the high quality magnesium alloy welding process, provides the technical support for themagnesium alloy widespread application.key word: Magnesium alloy Aluminum alloy The laser welds Plasma arc welding3材料介绍众所周知，由于镁和镁合金的焊接性能不好，所以，近年来，分别采用钨极氩弧焊、激光焊、激光一氩弧复合热源焊接，使其变形成镁合金AZ 31B，系统分析焊接接头的组织及性能。