Ti_(5)Si_(3)含量对SiCp/2009Al激光填粉焊接头组织性能的影响

Effect of Ti_(5)Si_(3) Content in Filler Powder on the Microstructure and Properties of SiCp/2009Al Laser Filler Welding Joint

SiC颗粒增强铝基复合材料在轨道交通领域拥有广阔的应用前景。但是该材料在熔化焊接过程中极易产生脆性相影响接头质量,这制约了SiC颗粒增强铝基复合材料的发展。运用Ti,Si元素补偿对Al_(4)C_(3)脆性相的抑制作用,对SiCp/2009Al复合材料进行激光填粉焊,并运用SEM,XRD分析焊接接头的微观结构,应用维氏硬度计、万能试验机分别测试接头的硬度和拉伸性能,以此分析Ti_(5)Si_(3)含量对接头组织及力学性能的影响。结果表明:Ti_(5)Si_(3)的加入对于抑制Al_(4)C_(3)脆性相的生成有显著作用,焊缝中未发现Al_(4)C_(3)脆性相;随着Ti_(5)Si_(3)含量的提高,焊缝组织中Al_(3)Ti的分布密度和尺寸先减小后增大,熔合区形态完整度先增加后降低,热影响区宽度先减小后增大;焊缝平均硬度随Ti_(5)Si_(3)含量提高而增加,接头的抗拉强度呈现先增大后减少的趋势,其中添加20%Ti_(5)Si_(3)粉末的焊接接头抗拉强度是添加50%Ti_(5)Si_(3)粉末的焊接接头强度的2.8倍。

SiC particle reinforced aluminum matrix composites have broad application prospects in the field of rail transit.However,this material is prone to brittle phases that affect the quality of joints during the melting welding process,which restricts the development of SiC particle reinforced aluminum matrix composites.Ti and Si element compensation is applied to suppress the brittle phase of Al_(4)C_(3) and laser powder welding of SiCp/2009Al composite materials.Ti and Si element compensation is used to suppress the brittle phase of Al_(4)C_(3),and laser powder welding is conducted on SiCp/2009Al composite materials.SEM and XRD are used to analyze the microstructure of the welded joint.The hardness and tensile properties of the joint are tested using a vickers hardness tester and a universal testing machine,respectively,in order to analyze the influence of Ti_(5)Si_(3) content on the microstructure and mechanical properties of the joint.The results indicate that the addition of Ti_(5)Si_(3) has a significant effect on inhibiting the decomposition of SiC particles and the formation of Al_(4)C_(3) brittle phase through their reaction with Al,but the Al_(4)C_(3) brittle phase is not found in the weld seam;with the increase of Ti_(5)Si_(3) content,the distribution density and size of Al_(3)Ti in the weld microstructure first decrease and then increase,the morphological integrity of the fusion zone first increases and then decreases,and the width of the heat-affected zone first decreases and then increases;with the increase of Ti_(5)Si_(3) content,and the tensile strength of the joint shows a trend of first increasing and then decreasing,the tensile strength of the welded joint with 20%Ti_(5)Si_(3) powder added is 2.8 times that of the welded joint with 50%Ti_(5)Si_(3) powder added.