【作者】 朱飞；

【导师】 雷玉成；

【作者基本信息】 江苏大学 ， 材料加工， 2006， 硕士

【摘要】 本文采用等离子弧焊接方法，以SiCp／6061Al为研究对象，系统的研究了在不添加和添加填充材料Ti合金两种情况下，焊接电流、焊接速度、填充材料厚度及保护气种类对铝基复合材料等离子弧焊焊缝组织、成分分布及性能的影响。 在不添加填充材料Ti合金的情况下对SiCp／6061Al进行等离子弧焊接时，等离子弧较高的热输入导致基体Al和增强相SiC颗粒发生有害界面反应：3SiC+4Al=Al₄C₃+3Si，生成大量针状脆性相Al₄C₃，并造成增强相SiC颗粒的大量减少和偏聚，导致焊接接头力学性能严重下降。 为此，试验中采用钛合金作为填充材料，对SiCp／6061Al进行原位合金化焊接；并将离子气由单一的Ar气变为以一定比例混合的N₂+Ar的混合气体。研究结果表明：原位增强元素Ti和离子气N₂的存在，有效的抑制了有害界面反应的发生，并生成了以匀态分布的新型增强相TiC、TiN和AlN颗粒，使得焊接接头的强度得到明显改善，达到母材的65％。进一步研究发现：增强相的种类及分布状态成为影响铝基复合材料原位合金化等离子弧焊接接头强度的主要因素。 利用有限元软件ANSYS对SiCp／6061Al原位合金化等离子弧焊的温度场进行模拟，并将模拟结果与焊缝的熔深试验测量值对比，验证了该模拟的有效性；在此基础上，探讨了不同焊接工艺参数下所形成的不同温度场分布对熔池中增强相种类及分布规律的影响，研究结果表明：对SiCp／6061Al原位合金化等离子弧焊接温度场的有效调节和优化是获得具有良好焊缝组织和力学性能接头的有效途径。更多还原

【Abstract】 In this paper, a systematic study on effect of welding parameters （welding current、 welding velocity、 thickness of alloying filler、 shielding gas） on the microstructure and distribution of welded joint in plasma arc welding for SiCp/6061Al was conducted with or without alloying filler Ti.The analysis on plasma arc welding for SiCp/6061 Al without filler showed thatdue to higher heat input, matrix Al and reinforcement SiC generate interface reaction（3SiC+4Al=Al₄C₃+3Si）, generating harmful fragile phase Al₄C₃, the number ofSiCp falling down and presenting local aggregation. Because of these reasons, thetensile strength of welded joint was decreased.So SiCp/6061 Al was welded by plasma arc with alloying filler Ti and the ionized gas was changed from simple Ar to N₂+Ar mixed in certain proportion. The results showed that due to the presence of alloying filler Ti and N₂, the harmful interface reaction was effectively restrained; the flowing property of molten pool was improved; even fresh reinforcing phases such as TiC、 TiN 、 AlN generated in welded joint. Whereas the performance of welded joint were improved to 65% of base metal. Further studies showed that species and distribution of reinforcing phase are principle factors for effect on performance of welded joint in "In-situ" weld-alloying/PAW of SiCp/6061 Al.In order to analyzed the effect of welding processing parameters on species and distribution of reinforcing phases visually and legibly, finite element software ANSYS was used to simulate transient temperature field for SiCp/6061 Al in "in—situ" weld alloying/plasma arc welding. The results showed that the calculated results approximately agreed with the experimental measured results. So the model was basically correct and credible. Based on the numerical solutions and experimental results, effect of temperature field in different welding process parameters（welding current、 welding velocity） on species and distribution of reinforcing phases was analyzed. The results show that adjusting and optimizing temperature field appropriately is an effective method to obtain welded joint with better microstructure and performance.更多还原