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采用YAG固体脉冲激光器对基于微纳复合粉体的铝合金薄板进行两面激光焊接试验。利用金相显微镜、扫描电子显微镜、万能试验机和显微硬度机等仪器分析了焊接接头的显微组织、拉伸性能和硬度分布。结果发现:添加纳米氧化铈的熔合区组织较未添加纳米颗粒时更加均匀,显微硬度也略有提高(约为115-125HV);纳米碳化硅的添加可打断枝晶区的生长连续性,熔合区显微硬度明显提高(最高值达135HV),但波动较大。添加纳米氧化铈和纳米碳化硅颗粒后,焊接试样拉伸强度分别达到母材的93.24%、95.5%,可见在相同工艺条件下,尽管由于激光吸收率的提高会加大母材软化现象,但并未对试样拉伸强度产生不利影响。
YAG solid-state pulsed laser was used to test the laser welding of aluminum alloy based on micro-nano composite powder. The microstructure, tensile properties and hardness distribution of welded joints were analyzed by means of optical microscope, scanning electron microscope, universal testing machine and microhardness tester. The results showed that the microstructure of the fused zone of the nano-sized cerium oxide was more uniform than that without the nano-particles and the microhardness slightly increased (about 115-125HV). The addition of nano-SiC could break the continuity of the dendritic zone , The micro-hardness of the fusion zone increased significantly (the highest value reached 135HV), but the fluctuation was larger. Adding nano-cerium oxide and nano-silicon carbide particles, the tensile strength of welded samples reached 93.24%, respectively, 95.5% of base metal, visible under the same process conditions, although due to the increase of laser absorption rate will increase the softening of the base metal, But did not adversely affect the tensile strength of the sample.