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Ti对SiCp/6092铝基复合材料激光焊焊缝组织和性能的影响

Effect of Ti on microstructure and properties of laser welding weld of SiC particle reinforced 6092 Al alloy matrix composite

  • 摘要: 采用不同厚度的Ti箔作为填充材料对SiCp/6092铝基复合材料进行激光焊接,分析不同含量Ti元素对焊缝组织和焊接接头力学性能的影响. 结果表明,Ti箔的加入可以有效改善熔池流动性,从而减少焊缝区的工艺型气孔. 同时,填加Ti箔可以避免激光直接照射在母材上引起的低熔点元素烧损. 在激光的照射下,Ti箔完全熔化并与在热传导作用下部分熔化的母材金属发生冶金反应,Ti元素含量过少时,界面反应得不到有效抑制,焊缝中仍分布有大量的脆性相,Ti元素对焊接接头的力学性能改善不明显;Ti元素含量过多时,Ti元素在熔池中未能扩散开,富余的Ti元素与Al元素反应生成Al3Ti. 过分长大的Al3Ti呈片状,将对接头的力学性能不利. 因此,向熔池中加入适量Ti元素有利于改善熔池冶金反应,从而提升接头力学性能,焊接接头的最大抗拉强度可达206 MPa.

     

    Abstract: Ti foils of different thickness are used as filler materials to analysis the effects of different amount of Ti elements on microstructure and mechanical properties during laser welding of SiCp/6092 aluminum matrix composites. The results show that the addition of Ti foil can effectively improve the fluidity of the molten pool, thereby reducing the technologic porosities in the weld zone. At the same time, adding Ti foil can avoid the low melting point element burnt caused by the direct laser irradiation on the base material. Under the irradiation of the laser, the Ti foil is completely melted and metallurgical reacted with the matrix metal which is melted by the action of heat conduction. When the content of Ti element is too little, the interface reaction can not be effectively suppressed, and a large number of brittle phases are still distributed in the weld. Ti element does not significantly improve the mechanical properties of the welded joint. When the content of Ti element is too much, the Ti element fails to diffuse in the molten pool, and the excess Ti element reacts with aluminum to form Al3Ti. The over-grown Al3Ti is in the shape of sheet, which will be detrimental to the mechanical properties of the joint. Therefore, adding an appropriate amount of Ti element to the molten pool is beneficial to improve the metallurgical reaction of the molten pool, thereby improving the mechanical properties of the joint, and the maximum tensile strength of the welded joint can reach 206 MPa.

     

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