SiC_w/6061Al铝基复合材料粉末夹层瞬间液相扩散焊接工艺

Pulverous interlayer transient liquid phase bonding craft of Al-based composite SiC_w/606Al

采用质量比为2∶1的铝铜混合金属粉末作为中间夹层,通过TLP扩散焊接工艺焊接了SiCw/6061Al铝基复合材料。结果表明,在真空度为1.33Pa、焊接预紧力20MPa的条件下,最佳工艺参数为:焊接温度620℃,保温时间60min。采用扫描电镜研究了焊缝的微观组织,发现较低温度下焊缝存在较多的孔洞。用电子探针分析焊缝周围元素分布,结果表明,在焊缝处富集较多的氧元素和镁元素。这是因为基体铝合金中的镁与铜粉颗粒表面的氧化铜以及焊接工件表面的氧化膜(Al2O3)发生置换反应,生成细小的MgO和Al2MgO4颗粒。该反应有利于减小氧化膜的影响,提高接头强度。

Using aluminum powder and copper powder as pulverous interlayer, Al-based composite SiC_w/6061 was welded by transient liquid phase bonding. Mass ratio of aluminum powder and copper powder is 2∶1, vacuum degree is 1.33MPa, and retightening load is 20MPa. The result of experiment shows that the optimum process parameters are: welding temperature 620℃, holding time 60min. Observing with scanning electronic microscope, many holes are found at weld lines if works pieces are welded at lower temperature. Distribution of elements around weld line is analyzed with electronic probe. The results indicate that O and Mg is enriched at weld line. Magnesium within aluminum alloy reacts with CuO and Al_2O_3 to produce MgO particles and Al_2MgO_4 particles respectively, which is favorable for restraining the effect of oxide film and enhancing mechanics properties of welded joints.