铝、钛合金薄板的高功率CO_2激光焊接工艺研究
文献类型：学位论文
| 作者 | 许国良 |
| 学位类别 | 博士 |
| 答辩日期 | 2001 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 程兆谷 |
| 关键词 | CO_2激光器 光束质量 焊接 铝合金 钛合金 薄板 |
| 中文摘要 | 本论文工作是结合国家“九五”重点科技攻关计划专题-“铝、镁、钛合金薄板的激光焊接工艺研究”（专题编号：96-B11-01-06-01）进行的，在国内首次采用自行研制的高功率CO_2激光器实现了铝、钛合金等材料的激光焊接，填补了国内在具有战略意义的作为结构材料的轻有色金属铝、钛合金CO_2激光焊接领域的空白。论文工作首先改进了激光器的光束质量，提高了焦点功率密度，具体体现在：在激光功率输出达到3kW时，光束发散全角小于2.0毫弧度，比原来指标提高1.5倍；设计加工了消球差的透射式聚焦系统和反射式非球面聚焦系统；利用我课题组的专利技术，通过调制的脉冲群开关技术控制主放电，实出了平均功率3kW以上的脉冲输出，使峰值功率提高了近2倍；用半共焦腔的“反演”特性以获得均匀、对称分布的激光输出光斑。文中系统地研究了激光焊接工艺参数（光束质量、功率、焊接速度、辅助气体等）对铝、钛合金材料焊接可行性的影响。采用高光束质量CO_2激光、对接缝的小孔效应和合适的其他工艺参数等关键技术突破铝合金对10.6um波长的CO_2激光的极高的初始表面反射率，使激光能量有效地耦合入工件中去。通过三路辅助气体的选用和功率、焊速的合理搭配，有效地避免钛合金焊接接头区域的污染。铝、钛合金薄板的最大焊接深度分别达3.5mm和5mm。焊后的机械性能测试表明某些铝、钛合金在合适的工艺规范下，焊接接头的性能接近或相当于母材。 |
| 英文摘要 | This paper is based on a "National ninth five-year key research project"-"Research on laser welding of aluminum, magnesium and titanium thin alloy plates" (Subject No. 96-B11-01-06-01). Using a high power CO_2 laser developed in our lab, a series of thin aluminum and titanium alloy plates were successfully welded for the first time in China. Since these alloys are widely used in industry as structure material for their light weight and high strength, it is of great importance. Firstly we improved beam quality of output laser and increased the intensity at the focusing spot. Detail works summed up as follows: 1) Beam divergence angle reached 2.0mrad at 3kW output power; 2) Two kinds of focusing system were developed: transmissive and reflective; 3) Adopting modulated pulse cluster to switch the main discharge, pulse laser output averaged 3kW was realized whose peak power was twice higher; 4) By the "inversion" of half-confocal resonator, uniform and symmetrical output pattern was obtained. Effects of processing parameters (beam quality, laser power, welding speed and assisting gas et al.) on weldability of aluminum and titanium alloy plates were highlighted. It is difficult to weld aluminum alloys for their high reflectivity at 10.6 micrometer wavelength. Some key techniques helped to break through this difficulty and enhanced the energy coupling efficiency. Those techniques included high beam quality, artificial keyhole caused by the gap between two butt plates and so on. For the titanium alloys, it is effective to prevent the pollution of the weld joints by the adoption of three gases blowing simultaneously and the optimum selection of laser power and welding speed. The weld depth of aluminum and titanium alloy plates reached 3.5mm and 5mm respectively. Microhardness and tensile test showed that for some aluminum and titanium alloys, mechanical properties could be near or equal to base material with suitable processing parameters. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15314]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 许国良. 铝、钛合金薄板的高功率CO_2激光焊接工艺研究[D]. 中国科学院上海光学精密机械研究所. 2001. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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