Fatigue property of Al-Li alloy friction stir welded lap joints
-
摘要: 通过疲劳寿命试验、疲劳断口和金相组织分析,研究了Al-Li合金搅拌摩擦焊搭接接头的疲劳性能,分析了接头前进侧热机影响区(TMAZ, Thermal-Mechanically Affected Zone)出现的"钩状缺陷"对其疲劳性能的影响.结果表明,钩状缺陷容易引起裂纹萌生及扩展,减小接头的有效承载板厚,适当缩短搅拌针长度可以改善钩状缺陷,提高接头力学性能.母材与搭接接头的疲劳S-N曲线研究表明:在高疲劳应力下,接头的疲劳寿命接近母材,但随着疲劳应力水平降低,接头的疲劳寿命急剧下降,200万循环周次下的疲劳强度仅达到80 MPa,为母材的35%.Abstract: Through the fatigue test, fracture characteristic and microstructure analyses, the fatigue property of the Al-Li alloy friction stir welded lap joints and the effect of "hooking defect" appearing at the thermal-mechanically affected zone(TMAZ) of advancing side on the joint fatigue property were studied. The results show that the cracks can easily initiate and extend from the location of hooking defect, leading to the decrease in the "effective sheet thickness"(EST) of material and damage to the joint fatigue behavior. The appropriate reduction of the pin length is proved one way of to improve the defects and mechanical property of joints. Furthermore, the established S-N curves show that the fatigue life of lap joints is close to base metal on the high fatigue stress. As the fatigue stress decreasing, the joint fatigue life sharply declines and the fatigue strength of joints at fatigue life N=2 106 is only 80 MPa, only equivalent to 35% that of base metal.
-
Key words:
- friction stir welding(FSW) /
- Aluminum-Lithium alloy(Al-Li) /
- fatigue /
- hooking defect
-
[1] 王大勇,冯吉才,王攀峰.搅拌摩擦焊接Al-Li合金接头的微观组织及力学性能[J].金属学报,2004,40(5):504-508
Wang Dayong,Feng Jicai,Wang Panfeng.Microstructures and mechanical properties of Al-Li alloy friction stir weld[J].Journal of Acta Metallurgica Sinica,2004,40(5):504-508(in Chinese)[2] Lertora E,Gambaro C.AA8090 Al-Li alloy FSW parameters to minimize defects and increase fatigue life[J].Int J Mater Form,2010,3:1003-1006 [3] Cavaliere P,Cabibbo M,Panella F.2198 Al-Li plates joined by friction stir welding:mechanical and microstructural behaviour[J].Materials and Design,2009,30:3622-3631 [4] Wei Shitong,Hao Chuanyong,Chen Jichun.Study of friction stir welding of 01420 aluminum-lithium alloy[J].Materials Science and Engineering,2007,452:170-177 [5] 栾国红.飞机制造中的搅拌摩擦焊技术及其发展[J].航空制造技术,2009,20:26-31
Luan Guohong.Fricition stir welding technology and its development in manufacturing of aircraft[J].Journal of Aeronautical Manufacturing Technology,2009,20:26-31(in Chinese)[6] 刘红兵,陈洁,占小红,等.铝合金搅拌摩擦焊搭接焊的研究概述[J].热加工工艺,2011,40(19):126-132
Liu Hongbing,Chen Jie,Zhan Xiaohong,et al.Review on friction stir lap welding of aluminum alloy[J].Journal of Hot Working Technology,2011,40(19):126-132(in Chinese)[7] 曹丽杰,张朝民,郭洋,等.铝合金搅拌摩擦焊接接头疲劳行为的研究[J].兵器材料科学与工程,2010,33(3):92-96
Cao Lijie,Zhang Chaomin,Guo Yang,et al.Fatigue behavior of friction stir welded aluminum alloy joints[J].Journal of Ordnance Material Science and Engineering,2010,33(3):92-96(in Chinese)[8] 周才智,杨新岐,栾国红.搅拌摩擦焊接头疲劳行为研究现状[J].稀有金属材料与工程,2006,35(7):1172-1176
Zhou Caizhi,Yang Xinqi,Luan Guohong.Research progress on the fatigue behavior of friction stir welded joints[J].Journal of Rare Metal Materials and Engineering,2006,35(7):1172-1176(in Chinese)[9] Fersini D,Pirondi A.Fatigue behaviour of Al2024-T3 friction stir welded lap joints[J].Engineering Fracture Mechanics,2007,74:468-480 [10] Liu H J,Fujii H,Maeda M,et al.Tensile properties and fracture locations of friction'stir-welded joints of 2017-T351 aluminum alloy[J].Journal of Materials Processing Technology,2003,142:692-696 [11] 郭晓娟,董春林,康举,等.搅拌摩擦焊搭接界面缺陷初步研究[C] //第十五次全国焊接学术会议论文集.北京:中国机械工程学会,2010
Guo Xiaojuan,Dong Chunlin,Kang Ju,et al.Preliminary study on interface defects of friction stir welded lap joints[C] //The 15th National Welding Conference.Beijing:Chinese Mechanical Engineering Society,2010(in Chinese)[12] 徐效东,杨新岐,吴铁,等.铝合金搅拌摩擦焊搭接接头工艺及组织性能研究[J].金属铸锻焊技术焊接学报,2010,39(15):125-129
Xu Xiaodong,Yang Xinqi,Wu Tie,et al.Study on microstructure and properties of friction stir welded lap joints of aluminum alloy[J].Journal of Hot Working Technology,2010,39(15):125-129(in Chinese)
点击查看大图
计量
- 文章访问数: 1838
- HTML全文浏览量: 31
- PDF下载量: 635
- 被引次数: 0