30%SiC_P/LD2复合材料的TIG焊研究

采用钨极氩弧焊的方法对30%SiCP/LD2高体积分数复合材料进行了焊接实验,研究了在同种TIG焊焊接规范参数下LD2-LD2、LD2-30%SiCP/LD2、30%SiCP/LD2-30%SiCP/LD2三种不同材料组合焊接性差异,分析了焊接热输入对接头强度的影响。实验结果表明:LD2-LD2焊后接头强度高于其他两种;焊接热输入过大和过小都会造成接头强度的损失。利用光学显微镜和扫描电镜观察分析了30%SiCP/LD2复合材料TIG焊接头强度损失的机理,认为接头区形成少量的气孔及SiC颗粒的偏聚是造成接头强度下降的主要原因,接头区未见Al-SiC界面反应现象。着重分析了气孔类型、形成原因及防止措施。在此基础上,通过合理的接头区坡口设计、选择合适的焊丝成分、制定合理的焊接工艺规范,认为采用钨极氩弧焊方法焊接30%SiCP/LD2高体积分数复合材料是可行的。

Investigation on TIG welding of 30% SiC_P/LD2 Composite

The joining characterics of 30% SiCP reinforced aluminum matrix composite (SiCP/reinforced AMC) were investigated by tungsten insert gas arc welding process(TIG).The weldability differences among LD2-LD2,LD2-30%SiCP/LD2,30%SiCP/LD2-30%SiCP/LD2 were also studied under the same welding technological parameters. The influences of welding heat input on joint strength were analyzed. The type,the forming reason and the avoiding measure of the porosities in the weld was analysed.The results show that the joint strength of LD2-LD2 is higher than the others. Too higher or too lower heat input can both make the joint strength decrease,which results from the unhomogeneous gather of the small amount of porosities and reinforcement SiC particles.Moreover there is no any interface reaction between base material aluminum and reinforcement phase SiC particle in the weld.It is feasible for TIG methods to weld high volume fraction SiCP /LD2 composites using reasonable joint slope design,the appropriate solder composition and reasonable welding technological parameters.