2219T87 铝合金焊接接头的常温蠕变行为及其预测Creep behavior and forecast of welded joint for 2219T87 aluminum alloy at room temperature

研究FSW 和TIG 焊两种连接态2219T87 铝合金焊接接头的常温蠕变行为，分析焊接工艺和蠕变应力条件对蠕变行为的影响。采用蠕变试验机考察试件300 h 内的拉伸蠕变和压缩蠕变性能，并通过实验数据曲线拟合预测焊接件在1×10⁵h 内相应的蠕变量。结果表明：相同应力水平下，压缩蠕变量比拉伸蠕变量小。相对于TIG焊，FSW 接头的质量更好(屈服强度更高)，其显微组织均匀细小且没有气孔缺陷，因此表现出的抗蠕变能力更好。当服役应力低于其屈服强度时，FSW 和TIG 焊接态2219T87 铝铜合金的1×10⁵ h 蠕变量均不超过1%。

The room temperature creep behavior of 2219T87 aluminum alloy welded joints processed by friction stir welding (FSW) or tungsten inert gas welding (TIG) arc welding was investigated. The effects of welding process and creep stress condition on the creep deformation were analyzed. The tensile and compressive creep properties of the joints in 300 h were real-time measured by the creep machine. Based on the measured data,the creep strain of the joints after 1×10⁵ h was calculated by curve-fitting method. The results show the creep strain of the samples in compressive test is smaller than that in tensile state under the same stress level. In comparison to TIG arc welding,friction stir welding generates better quality joints (with higher yield strength),which possess a fine,homogenous and no pores defect microstructure. Therefore,the FSW joint has a better creep resistance. In addition,when the creep stress is lower than the yield strength,the creep values of the 2219T78 aluminum alloy welded joints processed by FSW and TIG after 1×10⁵ h are less than 1%.

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