N2在等离子弧原位焊接SiCp/Al基复合材料中的作用

以0．8mm钛片作为填充材料，采用纯氩和氮氩混合等离子气体对SiCp／Al基复合材料进行等离子弧原位焊接，分析加入的N2对焊缝成形、焊缝组织和性能的影响。结果表明，随氮气体积分数增大，焊缝熔深也相应增大：增加氮气还改善了熔池中的热循环状态和冶金反应，生成TiN、AlN等新的增强相，有效地抑制脆性相的生成，改善了焊接接头的性能。力学性能实验表明，采用Ar＋N2作为离子气进行焊接时，焊缝硬度和强度都有提高。当N2体积分数约占15％时，拉伸强度达到最大值233．5MPa。

Effect of nitrogen on plasma arc in-situ welding of SiCp/Al MMCs

In order to analyze the weldability of SiC particle reinforced aluminum metal matrix composites(SiCp/Al MMCs),Plasma arc in-situ welding of SiCp/Al MMCs was carried out using pure argon and argon-nitrogen mixture as plasma gases with 0.8 mm thick titanium filler-plate as in-situ material.The effect of nitrogen addition into plasma gases on the appearance of weld,microstructure and mechanical properties was investigated.The results show that when the nitrogen volume increases,the weld penetration also correspondingly increases.The thermal cycle state and metallurgy response of the molten poor are also improved by adding nitrogen.A new composite reinforced by TiN,AlN is produced in the weld,effectively suppressing the formation of Al4C3,consequently ensuring the quality of joints.The mechanical testing results show that the microhardness and tensile strengths of joins welded by adding nitrogen are both increased.The highest tensile strength of joints is 233.5 MPa when the nitrogen volume is approximately 15%.