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通过在BT20钛合金电子束焊接过程中添加嵌料,改变接头熔合区的化学成分,研究成分的变化对其焊接接头焊缝区显微组织、显微硬度以及高周疲劳性能的影响。结果发现,成分调控在降低接头熔合区合金化程度的同时,还改变了熔合区的显微硬度分布。高周疲劳测试结果表明,成分调控BT20合金焊接接头的疲劳强度与传统焊接接头相当,比基体高;但是在780MPa的高应力水平下,疲劳寿命随疲劳峰值应力的增加迅速降低,样品在焊缝区断裂的几率增加,表明成分调控会降低焊接接头高应力水平下的疲劳性能。
The effects of composition changes on the microstructure, microhardness and high cycle fatigue properties of the weld zone of the welded joints were studied by adding inlay and changing the chemical composition of the fusion zone in BT20 titanium alloy electron beam welding. The results showed that the component regulation changed the microhardness distribution of the fusion zone while reducing the degree of alloying in the joint fusion zone. The results of high cycle fatigue test show that the fatigue strength of BT20 alloy welded joints controlled by components is equivalent to that of the traditional welded joints and higher than that of the base body. However, under the high stress level of 780MPa, the fatigue life decreases rapidly with the increase of peak fatigue stress. Zone fracture increases the probability that the composition of the control will reduce the fatigue strength of welded joints under high stress levels.