In-situ weld-alloying plasma arc welding of SiCp/Al MMC

Plasma arc welding was used to join SiCp/ml composite with titanium as alloying filler material. Microstructure of the weld was characterized by an optical microscope. The results show that the harmful needle-like phase Al4C3 is completely eliminated in the weld of SiCp/Al metal matrix composite（MMC） by in-situ weld-alloying/plasma arc welding with titanium as the alloying element. The wetting property between reinforced phase and Al matrix is improved, a stable weld puddle is gotten and a novel composite-material welded joint reinforced by TiN, AlN and TiC is produced. And the tensile-strength and malleability of the welded joints are improved effectively because of the use of titanium.     

Effect of temperature field on types and distribution of reinforcing phases in “in-situ” weld-alloying/PAW of SiC_p/6061Al

Based on theories of heat transfer,physical metallurgy and hydro-mechanical,in order to analyze the effect of welding parameters on species and distribution of reinforcing phases visually and legibly,finite element software ANSYS was used to simulate transient temperature field for SiC_p/AI in“in-situ”weld-alloying/plasma arc welding.The results show that the calculated results approximately agreed with the experimental measured results.So the model is 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 is analyzed.The results show that adjusting and optimizing temperature field appropriately is an effective method to obtain welded joint with better microstructure and property.     

Ti对SiCp/Al等离子弧焊焊缝组织的影响

对铝基复合材料进行等离子弧焊接,高温下基体Al与增强相SiC之间发生有害界面反应,生成脆性相Al4C3,严重降低焊接接头的力学性能．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,着重研究了合金化填充材料Ti对焊缝显微组织的影响．研究结果表明：合金化填充材料Ti的添加改善了基体与增强相间的润湿性,在一定程度上抑制了基体舢与增强相SiC之间界面反应的发生,抑制了脆性相Al4C3的生成,并获碍以TiN、MN为二次增强相均匀分布的焊缝显微组织,保证了焊接接头的力学性能．     

等离子弧焊接SiCp/Al基复合材料焊缝“原位”合金化分析

采用等离子弧焊焊接SiCp／Al基复合材料,以Ar＋N2为离子气,并以Ti作为合金化填充材料,研究了焊缝“原位”合金化元素Ti对焊缝显微组织的影响。结果表明,采用焊缝原位合金化方法焊接SiC颗粒增强铝基复合材料（sicp／A1MMCs）,可以有效抑制焊缝中针状脆性相Al4C3的形成,并且由于耶的加入,改善了增强相和Al基体之间的润湿性,形成了稳定的熔池,得到以均匀分布的TiN、AlN等为增强相的新型铝基复合材料焊缝,焊接性能得到有效提高。同时还研究了Ti的添加量对焊缝显微组织的影响,结果发现,随着耶含量的增加,焊缝中还生成如Ti5Si3等新的增强相。焊缝“原位”合金化等离子弧焊接是焊接SiCp／Al基复合材料的一种新方法。     

SiCp/6061 Al复合材料等离子弧焊工艺参数对焊缝组织及性能的影响

采用等离子弧焊接工艺研究铝基复合材料SiCp/6061Al的焊接性,借助X射线衍射、扫描电镜等手段分析接头组织,着重探讨了在填加和不填加合金化填充材料Ti的情况下,焊接电流、焊接速度对焊缝显微组织及焊接接头力学性能的影响机理,研究表明,在未填加材料Ti时,焊接工艺参数的改变并不能抑制有害相Al4C3的生成,只能改变其尺寸和数量;在填加填充材料Ti时,焊缝熔池中增强相的种类及分布是影响焊接接头性能的主要因素;适当调整焊接工艺参数有利于焊缝中心形成完全以新生颗粒TiC,TiN和AlN为增强相的完全原位反应区;同时减小新旧增强相共存区域的宽度,并消除增强相SiC颗粒的偏聚现象,从而提高了焊接接头的力学性能.