基于低强匹配理论的铝合金搅拌摩擦焊接头强化技术的研究
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摘要
搅拌摩擦焊具有接头质量好,应力变形小,疲劳强度高等优点,在航空、航天、船舶、车辆等载运工具制造技术领域已得到实际应用。但是热处理强化铝合金搅拌摩擦焊接头的过时效软化问题仍比较突出,通过工艺试验的方法来改善接头承载能力的效果还不明显。
本文采用数字图像相关技术对6061-T6铝合金搅拌摩擦焊接头的非均匀变形行为及其机理进行了研究,对拉伸载荷作用下接头的力学响应进行了有限元模拟,对接头几何尺寸对应力应变分布规律的影响进行了分析,为优化搅拌摩擦焊工艺和改善接头承载能力提供了科学依据。
拉伸载荷作用下6061-T6铝合金搅拌摩擦焊接头表现出显著的非均匀变形的特征,接头变形随载荷增大从均匀弹性变形向非均匀塑性变形转变,从接头前进侧应变集中向后退侧应变集中转变,其非均匀变形的规律取决于接头各区屈服强度大小及应变硬化能力的相对关系。
采用常规的硬度测试和先进的数字图像相关应变测试结果相结合的方法,可以更为准确地确定搅拌摩擦焊接头各区的位置、尺寸、形状。基于等应力假设和全场应变测试结果,可以获得接头各区局部的力学性能和应力应变关系。在此基础上,实现了对6061-T6铝合金搅拌摩擦焊接头拉伸载荷作用下力学行为的有限元模拟,模拟结果与实验结果具有较好的一致性。
采用有限元模拟的方法研究了接头各区几何尺寸形状变化对拉伸载荷作用下6061-T6铝合金搅拌摩擦焊接头的力学响应。随着接头热影响区、热塑性影响区和焊核区尺寸的减小,母材的拘束作用增强,热影响区、焊核区、热塑性影响区的应力应变减小,接头承载能力得到提高。
Friction stir welding has many advantages such as good joint quality, low residual stress and distortion, and high fatigue strength, so it has been used in the manufacturing of aeronautics, astronautics, shipbuilding and vehicle. But, to heat treatment strengthening type aluminum alloy, over-aging still is a severe problem up to now and welding processing optimization has still not evident effect to the improvement of load bearing ability.
In this paper, the heterogeneous deformation behavior and mechanism of friction stir welding joint of6061-T6Aluminum alloy by digital image correlation. The finite element simulation of mechanical response of joint was conducted under tensile load. The influence of joint geometry on the stress and strain was analyzed. Science foundation was established for the optimization of friction stir welding processing and the improvement of the load bearing ability of joint.
The position and geometry of micro-zone of friction stir welding joint can be correctly identified by the combination of traditional micro hardness measurement and strain measurement of advanced digital image correlation. Based on iso-stress condition and the full stain results, the local mechanical properties and stress-train relation can be obtained. The finite element simulation of mechanical behavior of friction stir welding joint of6061-T6Aluminum alloy was realized under tensile load. The results of the simulation and experiment have good similarity.
The influence of the geometry variation of local micro-zone of friction stir welding joint on mechanical response under tensile load was studied by finite element simulation. With the decreased the sizes of heat affect zone, thermally-mechanical zone, and welding nugget, the constraint of the base material is increased, the stress and strain of the heat affect zone, thermally-mechanical zone, and welding nugget are decreased. As a result, the load bearing ability of friction stir welding is improved.
本文采用数字图像相关技术对6061-T6铝合金搅拌摩擦焊接头的非均匀变形行为及其机理进行了研究,对拉伸载荷作用下接头的力学响应进行了有限元模拟,对接头几何尺寸对应力应变分布规律的影响进行了分析,为优化搅拌摩擦焊工艺和改善接头承载能力提供了科学依据。
拉伸载荷作用下6061-T6铝合金搅拌摩擦焊接头表现出显著的非均匀变形的特征,接头变形随载荷增大从均匀弹性变形向非均匀塑性变形转变,从接头前进侧应变集中向后退侧应变集中转变,其非均匀变形的规律取决于接头各区屈服强度大小及应变硬化能力的相对关系。
采用常规的硬度测试和先进的数字图像相关应变测试结果相结合的方法,可以更为准确地确定搅拌摩擦焊接头各区的位置、尺寸、形状。基于等应力假设和全场应变测试结果,可以获得接头各区局部的力学性能和应力应变关系。在此基础上,实现了对6061-T6铝合金搅拌摩擦焊接头拉伸载荷作用下力学行为的有限元模拟,模拟结果与实验结果具有较好的一致性。
采用有限元模拟的方法研究了接头各区几何尺寸形状变化对拉伸载荷作用下6061-T6铝合金搅拌摩擦焊接头的力学响应。随着接头热影响区、热塑性影响区和焊核区尺寸的减小,母材的拘束作用增强,热影响区、焊核区、热塑性影响区的应力应变减小,接头承载能力得到提高。
Friction stir welding has many advantages such as good joint quality, low residual stress and distortion, and high fatigue strength, so it has been used in the manufacturing of aeronautics, astronautics, shipbuilding and vehicle. But, to heat treatment strengthening type aluminum alloy, over-aging still is a severe problem up to now and welding processing optimization has still not evident effect to the improvement of load bearing ability.
In this paper, the heterogeneous deformation behavior and mechanism of friction stir welding joint of6061-T6Aluminum alloy by digital image correlation. The finite element simulation of mechanical response of joint was conducted under tensile load. The influence of joint geometry on the stress and strain was analyzed. Science foundation was established for the optimization of friction stir welding processing and the improvement of the load bearing ability of joint.
The position and geometry of micro-zone of friction stir welding joint can be correctly identified by the combination of traditional micro hardness measurement and strain measurement of advanced digital image correlation. Based on iso-stress condition and the full stain results, the local mechanical properties and stress-train relation can be obtained. The finite element simulation of mechanical behavior of friction stir welding joint of6061-T6Aluminum alloy was realized under tensile load. The results of the simulation and experiment have good similarity.
The influence of the geometry variation of local micro-zone of friction stir welding joint on mechanical response under tensile load was studied by finite element simulation. With the decreased the sizes of heat affect zone, thermally-mechanical zone, and welding nugget, the constraint of the base material is increased, the stress and strain of the heat affect zone, thermally-mechanical zone, and welding nugget are decreased. As a result, the load bearing ability of friction stir welding is improved.
引文
[1]孙红梅.6082-T6铝合金搅拌摩擦焊接头组织和性能的研究[硕士学位论文][D].北京交通大学,2009：21-24.
[2]刘会杰,陈迎春,冯吉才.中国搅拌摩擦焊技术的研究,焊接[J].2004(12)：5-9。
[3]云彬.搅拌摩擦焊---最具革命性的焊接新技术.专访报导.航空制造技术.2003(11).
[4]关桥.搅拌摩擦焊(FSW)在国防工业中的应用现状与发展前景[C].搅拌摩擦焊技术推广交流会.2006：5-9
[5]Ericsson M. Influence of welding speed on the fatigue of friction stir welds and comparison with MIG and TIG[J]. International Journal of Fatigue, 2003,25(12):1382.
[6]ZHAO Y, FU J, ZHANG P, et al. Research on Effect of Welding Ways on Joint Performance of
Aluminum Alloy[J]. Journal of Jiangsu, 2006, 02:92.
[7]周万盛,姚君山.铝及铝合金的焊接[M].北京,机械工业出版社,2006：312.
[8]栾国红.搅拌摩擦焊技术应用现状及发展趋势[J].航空制造技术,2007：148-151.
[9]关桥,栾国红.搅拌摩擦焊的现状与发展[C].第十一次全国焊接会议论文集.2005
[10]C.卡默,卢惠明.铝手册[M].北京,化学工业出版社.2009.
[11]《铝合金热处理》编写组.铝合金热处理[M].北京,冶金工业出版社,1972：65-69.
[12]王群骄.有色金属热处理技术[M].北京,化学工业出版社.2008.
[13]冯银成.6061铝合金热变形及时效过程中的组织力学行为研究[硕士学位论文][D].湖南大学,2010：13.
[14]Cabibbo M, Spigarelli S, Evangelista E. A TEM investigation on the effect of semisolid forming on precipitation processes in an Al-Mg-Si Alloy[J]. Materials Characterization, 2002, 49(3):196.
[15]胡尊艳.焊后时效对6061-T6铝合金搅拌摩擦焊接头组织和性能的影响[硕十学位论文][D].北京交通大学,2008：8-9.
[16]Hakan Ayd n, Ali Bayram, Agah Ug uz.e.t. Tensile properties of friction stir welded joints of 2024 aluminum alloys in different heat-treated-state[J]. Materials and Design 2009(30):2211-2221.
[17]Wade M. Weld parameter and post weld heat treatment effects on 6xxx series friction stir weld properties [Dissertation][D]. University of South Carolina, 2007:36.
[18]乔文广.时效处理对2024-T3搅拌摩擦焊接头组织及性能的影响[硕士学位论文][D].天津大学,2008：4.
[19]邹吉权,张玉凤,霍立兴.用滑移线场方法评价低匹配接头的承载能力[J].焊接技术,2003,32(1)：4-7
[20]赵俊丽,尹永霞.900MPa高强钢低匹配焊接研究及应用高强钢低匹配焊接研究及应用[J].焊接技术,2009,38(9)：21-25.
[21]胡继超,赵智力等.低匹配对接接头的“等承载设计”及拉伸疲劳[J].机械工程学报,2010,46(10)：75-80.
[22]胡宗文,王元清等.应力集中对钢结构厚板脆性破坏的影响分析[J].低温建筑技术,2010, 1：1-4.
[23]Lockwood W D, Tomaz B, Reynolds A. Mechanical response of friction stir welded AA2024: experiment and modeling[J]. Materials Science and Engineering: A, 2002, 323(1-2):348-353.
[24]Nielsen K L, Pardoen T, Tvergaard V, et al. Modeling of plastic flow localisation and damage development in friction stir welded 6005A aluminum alloy using physics based strain hardening law[J]. International Journal of Solids and Structures, Elsevier Ltd,2010,47(18-19): 2359-2370.
[25]Nielsen K L. Ductile damage development in friction stir welded aluminum (AA2024) joints[J]. Engineering Fracture Mechanics, 2008, 75(10):2795-2811.
[26]万妮.基于数字图像处理的材料微结构演化实验研究[硕士学校论文][D].南昌大学,2007：1-58.
[27]范子杰,桂良进等.双相钢板料的单向拉伸断裂失效研究(Ⅰ)数字图像相关技术试验[J].应用力学学报,2010,27(2)：380-383.
[28]崔小鹏,刘美华等.数字图像相关技术在材料表面力学性能测试中的应用[C].大连第十一届全国实验力学学术会议.2005：1048-1053.
[29]方钦志,李慧敏,欧阳小东等.图像相关法在高分子材料拉伸性能研究中的应用[J].实验力学,2006,21(4)：459-465.
[30]刘红欣,吴凤琳等.利用数字图像相关技术观测低碳钢拉伸滑移线[J].上海大学力学实验中心.
[31]Michael A Sutton. Digital Image Correlation for Shape and Deformation Measusrements[G]. Springer Handbook of Experimental Solid Mechanics. 2008:565-600.
[32]A. P. Reynolds, F.Duvall R A. Digital image correlation for determination of weld and base metal constitutive behavior[J]. WELDING JOURNAL-NEW, 1999:355-360.
[33]Lockwood W D, Reynolds a. P. Simulation of the global response of a friction stir weld using local constitutive behavior[J]. Materials Science and Engineering: A, 2003,339(1-2):35-42.
[34]Leitao C, Galvao I, Leal R M, et al. Determination of local constitutive properties of aluminum friction stir welds using digital image correlation[J]. Materials & Design, 2012, 33:69-74.
[35]Genevois C, Deschamps a., Vacher P. Comparative study on local and global mechanical properties of 2024 T351,2024 T6 and 5251 O friction stir welds[J]. Materials Science and Engineering: A, 2006, 415(1-2): 162-170.
[36]赵柏森,王怀建,李海峰.金属塑性成形工艺有限元数值模拟技术.金属铸锻焊技术[J].2010(39)：86-90.
[37]张帆.材料性能学[M].上海,上海交通大学出版社.2009.
[38]张洪信.有限元基础理论与ANSYS应用[M].北京,机械工业出版社,2006.
[39]姜年朝等.有限元分析误差校验研究[J].机械与电子.2009(4)：66-67.
[40]张彦华.焊接强度分析[M].西安,西北工业大学出版社,2011：63-71.
[2]刘会杰,陈迎春,冯吉才.中国搅拌摩擦焊技术的研究,焊接[J].2004(12)：5-9。
[3]云彬.搅拌摩擦焊---最具革命性的焊接新技术.专访报导.航空制造技术.2003(11).
[4]关桥.搅拌摩擦焊(FSW)在国防工业中的应用现状与发展前景[C].搅拌摩擦焊技术推广交流会.2006：5-9
[5]Ericsson M. Influence of welding speed on the fatigue of friction stir welds and comparison with MIG and TIG[J]. International Journal of Fatigue, 2003,25(12):1382.
[6]ZHAO Y, FU J, ZHANG P, et al. Research on Effect of Welding Ways on Joint Performance of
Aluminum Alloy[J]. Journal of Jiangsu, 2006, 02:92.
[7]周万盛,姚君山.铝及铝合金的焊接[M].北京,机械工业出版社,2006：312.
[8]栾国红.搅拌摩擦焊技术应用现状及发展趋势[J].航空制造技术,2007：148-151.
[9]关桥,栾国红.搅拌摩擦焊的现状与发展[C].第十一次全国焊接会议论文集.2005
[10]C.卡默,卢惠明.铝手册[M].北京,化学工业出版社.2009.
[11]《铝合金热处理》编写组.铝合金热处理[M].北京,冶金工业出版社,1972：65-69.
[12]王群骄.有色金属热处理技术[M].北京,化学工业出版社.2008.
[13]冯银成.6061铝合金热变形及时效过程中的组织力学行为研究[硕士学位论文][D].湖南大学,2010：13.
[14]Cabibbo M, Spigarelli S, Evangelista E. A TEM investigation on the effect of semisolid forming on precipitation processes in an Al-Mg-Si Alloy[J]. Materials Characterization, 2002, 49(3):196.
[15]胡尊艳.焊后时效对6061-T6铝合金搅拌摩擦焊接头组织和性能的影响[硕十学位论文][D].北京交通大学,2008：8-9.
[16]Hakan Ayd n, Ali Bayram, Agah Ug uz.e.t. Tensile properties of friction stir welded joints of 2024 aluminum alloys in different heat-treated-state[J]. Materials and Design 2009(30):2211-2221.
[17]Wade M. Weld parameter and post weld heat treatment effects on 6xxx series friction stir weld properties [Dissertation][D]. University of South Carolina, 2007:36.
[18]乔文广.时效处理对2024-T3搅拌摩擦焊接头组织及性能的影响[硕士学位论文][D].天津大学,2008：4.
[19]邹吉权,张玉凤,霍立兴.用滑移线场方法评价低匹配接头的承载能力[J].焊接技术,2003,32(1)：4-7
[20]赵俊丽,尹永霞.900MPa高强钢低匹配焊接研究及应用高强钢低匹配焊接研究及应用[J].焊接技术,2009,38(9)：21-25.
[21]胡继超,赵智力等.低匹配对接接头的“等承载设计”及拉伸疲劳[J].机械工程学报,2010,46(10)：75-80.
[22]胡宗文,王元清等.应力集中对钢结构厚板脆性破坏的影响分析[J].低温建筑技术,2010, 1：1-4.
[23]Lockwood W D, Tomaz B, Reynolds A. Mechanical response of friction stir welded AA2024: experiment and modeling[J]. Materials Science and Engineering: A, 2002, 323(1-2):348-353.
[24]Nielsen K L, Pardoen T, Tvergaard V, et al. Modeling of plastic flow localisation and damage development in friction stir welded 6005A aluminum alloy using physics based strain hardening law[J]. International Journal of Solids and Structures, Elsevier Ltd,2010,47(18-19): 2359-2370.
[25]Nielsen K L. Ductile damage development in friction stir welded aluminum (AA2024) joints[J]. Engineering Fracture Mechanics, 2008, 75(10):2795-2811.
[26]万妮.基于数字图像处理的材料微结构演化实验研究[硕士学校论文][D].南昌大学,2007：1-58.
[27]范子杰,桂良进等.双相钢板料的单向拉伸断裂失效研究(Ⅰ)数字图像相关技术试验[J].应用力学学报,2010,27(2)：380-383.
[28]崔小鹏,刘美华等.数字图像相关技术在材料表面力学性能测试中的应用[C].大连第十一届全国实验力学学术会议.2005：1048-1053.
[29]方钦志,李慧敏,欧阳小东等.图像相关法在高分子材料拉伸性能研究中的应用[J].实验力学,2006,21(4)：459-465.
[30]刘红欣,吴凤琳等.利用数字图像相关技术观测低碳钢拉伸滑移线[J].上海大学力学实验中心.
[31]Michael A Sutton. Digital Image Correlation for Shape and Deformation Measusrements[G]. Springer Handbook of Experimental Solid Mechanics. 2008:565-600.
[32]A. P. Reynolds, F.Duvall R A. Digital image correlation for determination of weld and base metal constitutive behavior[J]. WELDING JOURNAL-NEW, 1999:355-360.
[33]Lockwood W D, Reynolds a. P. Simulation of the global response of a friction stir weld using local constitutive behavior[J]. Materials Science and Engineering: A, 2003,339(1-2):35-42.
[34]Leitao C, Galvao I, Leal R M, et al. Determination of local constitutive properties of aluminum friction stir welds using digital image correlation[J]. Materials & Design, 2012, 33:69-74.
[35]Genevois C, Deschamps a., Vacher P. Comparative study on local and global mechanical properties of 2024 T351,2024 T6 and 5251 O friction stir welds[J]. Materials Science and Engineering: A, 2006, 415(1-2): 162-170.
[36]赵柏森,王怀建,李海峰.金属塑性成形工艺有限元数值模拟技术.金属铸锻焊技术[J].2010(39)：86-90.
[37]张帆.材料性能学[M].上海,上海交通大学出版社.2009.
[38]张洪信.有限元基础理论与ANSYS应用[M].北京,机械工业出版社,2006.
[39]姜年朝等.有限元分析误差校验研究[J].机械与电子.2009(4)：66-67.
[40]张彦华.焊接强度分析[M].西安,西北工业大学出版社,2011：63-71.