The EBW joint of TC4-DT titanium alloy with thickness of 50mm is conducted to invest to the microstructures and fatigue properties in differrent location of joint, and compared with the base metal of TC4-DT titanium alloy. Based on the observation for micro-structure and testing of fatigue property sample, it shows that the 2Nf fatigue span of TC4-DT titanium alloy EBW joint is equal basically to those of base metal when the Ac, /2 expermental strain amplitude is lower than 0.6%. With the increasing of plastic strain amplitude, the difference between the fatigue span of joint in the upper postion and lower position and base metal occurs obvoiusly, in which the 2Nf fatigue span of base metal is the highest, and the lowest in the upper position.%通过对TC4-DT钛合金母材、电子束焊接接头显微组织的分析及焊接接头不同位置疲劳性能的测试,研究了焊接接头显微组织特点,比较了母材与焊接接头不同位置处的低周疲劳性能,讨论了不同应变水平下接头的断口形貌.结果表明,当疲劳应变幅△εt/2小于0.6％时,TC4-DT钛合金母材与接头的疲劳寿命2Nf基本相同,当疲劳应变幅△εt/2大于0.6％时,随着塑性变形应变幅的增大,母材与焊接板材上、下层处的2Nf差异逐渐明显,其中母材处的2Nf最高,焊接板材上层处的2Nf最低.
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