(1. 沈陽航空航天大學(xué) 航空航天工程學(xué)部，沈陽 110136； 2. 北京航空航天大學(xué) 機(jī)械工程與自動(dòng)化學(xué)院，北京 100191)
摘 要: 利用軸肩直徑為15 mm的鎢錸合金攪拌頭對(duì)2.5 mm厚TC4鈦合金進(jìn)行攪拌摩擦焊，重點(diǎn)分析接頭成形、顯微組織與拉伸性能。結(jié)果表明：焊核區(qū)的橫截面形貌呈現(xiàn)典型的“碗形”；當(dāng)轉(zhuǎn)速小于200 r/min時(shí)，焊接過程中的溫度峰值低于β相相變溫度。組成焊核的攪拌針作用區(qū)常出現(xiàn)“撕裂”型缺陷，其主要與焊接過程中的焊接拉應(yīng)力有關(guān)；降低攪拌頭的旋轉(zhuǎn)速度有利于減小、甚至消除“撕裂”型缺陷。低于相變溫度下獲得的無缺陷焊接接頭的抗拉強(qiáng)度幾乎與母材的等同，拉伸測(cè)試后的斷口由大量韌窩組成，為典型的韌性斷裂。
關(guān)鍵字: TC4鈦合金；攪拌摩擦焊；抗拉強(qiáng)度；撕裂型缺陷；相變溫度
（1. Faculty of Aerospace Engineering, Shenyang Aerospace University, Shenyang 110136, China; 2. School of Mechanical Engineering and Automation, Beihang University, Beijing 100191, China）
Abstract:TC4 titanium alloy with thickness of 2.5 mm was friction stir welded using W-Re rotational tool with shoulder diameter of 15 mm. The formation, microstructure and tensile property of FSW joint were mainly discussed. The results show that nugget zone (NZ) of cross section presents typical bowl-like shape. When rotating speed is lower than 200 r/min, the peak temperature during welding is below β-phase transus temperature. The tearing defect often appears in pin affected zone of NZ, which results from the welding tensile stress during welding. Decreasing the rotating speed is beneficial to reduce and even eliminate the tearing defect. The defect-free FSW joint attained below β-phase transus temperature owns high tensile strength, which is almost equal to that of base metal. The fracture surface is composed of plenty dimples, presenting the typical ductile fracture.
Key words: TC4 titanium alloy; friction stir welding; tensile strength; tearing defect; phase transus temperature
