Abstract Al-Li alloy 2198 exhibits good combination of toughness and strength but its application is strongly limited by the poor weldability due to the formation of porosities during fusion-welding. This is the first study proposing and verifying a new approach to produce defect-free laser welds of poorly fusion-weldable Al-Li alloy 2198 with applied external pressure, i.e., feasibility of laser pressure welding to Al-Li alloy 2198 was examined. The microstructures associated with tensile shear behavior of laser pressure welded Al-Li alloy 2198 obtained at various welding parameters were analyzed. The results showed that formation of the welding defect in the weld could be successfully suppressed by applying laser pressure welding, even without shielding gas. Three microstructural zones, including the chill zone, the columnar zone and the equiaxed zone were observed in the fusion zone. Size of fusion zone and area fraction of porosities generally increased with increasing roller pressure and welding heat-input, and they dominantly affected the tensile shear behavior, including the peak load and the failure mode, of the weld.

中文翻译：

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Al-Li 合金 2198 的激光压力焊接：焊接参数对与机械性能相关的熔合区特性的影响

摘要 2198铝锂合金具有良好的韧性和强度组合，但由于在熔焊过程中形成气孔，其可焊性较差，严重限制了其应用。这是第一项研究提出并验证了在施加外部压力的情况下生产可熔焊性较差的 Al-Li 合金 2198 的无缺陷激光焊缝的新方法，即研究了激光压力焊接到 Al-Li 合金 2198 的可行性。分析了在不同焊接参数下获得的与激光压力焊接的铝锂合金 2198 的拉伸剪切行为相关的微观结构。结果表明，即使没有保护气体，激光压力焊接也可以成功抑制焊缝中焊接缺陷的形成。三个显微结构区，包括冷区，在熔合区观察到柱状区和等轴区。熔合区的大小和孔隙面积分数通常随着辊压力和焊接热输入的增加而增加，它们主要影响焊缝的拉伸剪切行为，包括峰值载荷和失效模式。