Influence of Defect Depth of Kissing Bond on Fatigue Strength of AA5083 FSW Butt Joints
-
摘要: 针对具有吻接缺陷的5083铝合金板搅拌摩擦焊(FSW)对接接头试件,探索了吻接缺陷对搅拌摩擦焊对接接头疲劳强度的影响。使用维氏显微硬度仪测量了试件接头焊缝横截面硬度分布,测试结果显示,硬度值分布大致呈W趋势。采用MTS809疲劳测试机对试件进行疲劳测试,得到了不同吻接深度拉伸式样的名义应力-寿命关系。对疲劳断口进行SEM扫描并测量了接头吻接缺陷深度,发现疲劳裂纹均起源于吻接缺陷区域。通过有限元软件ABAQUS对不同吻接深度试件进行了应力应变分析,分别采用缺口应力法和局部应力应变法对试件进行了疲劳寿命预测。预测结果表明,缺口应力法在低周疲劳预测时效果较好。Abstract: For 5083 aluminum alloy friction stir welded(FSW) butt joints, the effect of the kissing bonding defect depth on the fatigue strength of friction stir welded joints was studied. The Vickers hardness distribution on the joint cross-section was measured via Microhardness tester, the test results showed that the hardness value distribution is almost "W" shape. The nominal stress-fatigue life relationship of specimens with different kissing bond depths were obtained under the constant amplitude fatigue loading on MTS809 fatigue testing machine. The tensile fatigue fractures were observed via scanning electron microscope(SEM)and measured the kissing bond depth, the results showed that the cracks all originated from the kissing bonding defect area. The finite element model for stress and strain calculation was established via ABAQUS software, with the results from finite element analysis, the fatigue lives of specimens were predicted with the notch stress method and local stress-strain method. The results showed that notch stress method is more effective for the low cycle fatigue life prediction.
-
表 1 5083铝合金主要化学成分
% w(Si) w(Cu) w(Mg) w(Zn) w(Mn) w(Ti) w(Cr) w(Fe) ≤0.4 ≤0.1 4.0~4.9 ≤0.25 0.4~1.0 ≤0.15 0.05~0.25 ≤0.4 表 2 试件最大载荷、实验寿命及吻接深度
试件编号 最大载荷/
MPa实验疲劳
寿命/次吻接深度/
mmFb007 196.078 431 1 771 0.51 Fb002 176.470 588 3 174 0.49 Fb016 149.019 608 4 758 0.51 Fb009 129.411 765 7 687 0.49 Fb015 123.529 412 5 036 0.51 Fb005 117.647 059 7 514 0.51 Fb021 101.960 784 8 948 0.48 Fb022 94.117 647 1 46 542 0.49 Fb013 90.196 078 4 52 431 0.52 Fb027 87.254 902 59 606 0.51 Fb023 205.882 353 4 196 0.31 Fb008 168.627 451 3 039 0.55 Fb017 143.137 255 5 200 0.55 Fb018 133.333 333 11 527 0.45 Fb019 113.725 490 5 049 0.71 Fb020 109.803 922 7 086 0.65 表 3 5083铝合金疲劳参数[17]
疲劳强度
系数σ′f疲劳延性
系数ε′f疲劳强度
指数b疲劳延性
指数c711 MPa 0.405 -0.122 -0.692 -
[1] UTHAYAKUMAR M, BALASUBRAMANIAN V, RANI A M A, et al. Effects of welding on the fatigue behaviour of commercial aluminum AA-1100 joints[J]. IOP Conference Series: Materials Science and Engineering, 2018, 346: 012065 doi: 10.1088/1757-899X/346/1/012065 [2] 佟建华, 张坤, 林松, 等. 搅拌摩擦焊和熔化极气体保护焊6082铝合金疲劳性能分析[J]. 焊接学报, 2015, 36(7): 105-108 https://www.cnki.com.cn/Article/CJFDTOTAL-HJXB201507025.htmTONG J H, ZHANG K, LIN S, et al. Comparison of fatigue property of 6082 aluminum alloy joint by friction stir welding and metal inert-gas welding[J]. Transactions of the China Welding Institution, 2015, 36(7): 105-108 (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-HJXB201507025.htm [3] 戴启雷, 孟立春, 梁志芳, 等. A6N01-T5合金FSW和MIG焊接头疲劳裂纹扩展行为的对比[J]. 焊接学报, 2015, 36(9): 9-12, 38 https://www.cnki.com.cn/Article/CJFDTOTAL-HJXB201509003.htmDAI Q L, MENG L C, LIANG Z F, et al. Comparison of fatigue crack propagation behavior of friction stir welded and metal inert-gas welded A6N01 joints[J]. Transactions of the China Welding Institution, 2015, 36(9): 9-12, 38 (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-HJXB201509003.htm [4] 李继忠, 孙占国, 高崇, 等. 根部未焊透对搅拌摩擦焊接接头力学性能的影响[J]. 电焊机, 2014, 44(4): 18-22 https://www.cnki.com.cn/Article/CJFDTOTAL-DHJI201404012.htmLI J Z, SUN Z G, GAO C, et al. Influence the lack of penetration on the mechanical properties of friction stir welded joints[J]. Electric Welding Machine, 2014, 44(4): 36-40 (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-DHJI201404012.htm [5] SALVATI E, EVERAERTS J, KAGEYAMA K, et al. Transverse fatigue behaviour and residual stress analyses of double sided FSW aluminium alloy joints[J]. Fatigue & Fracture of Engineering Materials & Structures, 2019, 42(9): 1980-1990 doi: 10.1111/ffe.13068 [6] 姬书得, 孟祥晨, 黄永宪, 等. 搅拌头旋转频率对静止轴肩搅拌摩擦焊接头力学性能的影响规律[J]. 焊接学报, 2015, 36(1): 51-54 https://www.cnki.com.cn/Article/CJFDTOTAL-HJXB201501013.htmJI S D, MENG X C, HUANG Y X, et al, Effect of rotational velocity of tool on mechanical properties of stationary shoulder friction stir welding[J]. Transactions of the China Welding Institution, 2015, 36(1): 51-54 (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-HJXB201501013.htm [7] OKADA T, MACHIDA S, NAKAMURA T. Corrosion resistance evaluation and effects of prior corrosion and stress on fatigue behavior of friction stir welded AA2024-T3[J]. Corrosion, 2018, 74(2): 169-180 doi: 10.5006/2447 [8] 张欣盟, 何广忠, 王贝贝, 等. 氧化膜对6082铝合金搅拌摩擦焊接头疲劳性能的影响[J]. 材料研究学报, 2019, 33(4): 299-305 https://www.cnki.com.cn/Article/CJFDTOTAL-CYJB201904008.htmZHANG X M, HE G Z, WANG B B, et al. Influence of oxide film on fatigue property of friction stir welded 6082 al alloy[J]. Chinese Journal of Materials Research, 2019, 33(4): 299-305 (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-CYJB201904008.htm [9] 金玉花, 吴永武, 王希靖, 等. 滚动轧制对铝合金搅拌摩擦焊接头性能的影响[J]. 焊接学报, 2019, 40(4): 50-54 https://www.cnki.com.cn/Article/CJFDTOTAL-HJXB201904009.htmJIN Y H, WU Y W, WANG X J, et al, Effect of rolling on friction stir welded joints of aluminum alloy[J]. Transactions of the China Welding Institution, 2019, 40(4): 50-54 (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-HJXB201904009.htm [10] 邓彩艳, 高仁, 龚宝明, 等. 7050铝合金搅拌摩擦焊接头超高周疲劳性能[J]. 焊接学报, 2018, 39(11): 114-118 https://www.cnki.com.cn/Article/CJFDTOTAL-HJXB201811023.htmDENG C Y, GAO R, GONG B M, et al. Research on ultra-high-cycle fatigue properties of 7050 aluminum alloy FSW welded joints[J]. Transactions of the China Welding Institution, 2018, 39(11): 114-118 (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-HJXB201811023.htm [11] 乔柯, 王快社, 王文, 等. 搅拌摩擦焊接AZ31镁合金低周疲劳性能[J]. 稀有金属材料与工程, 2019, 48(3): 788-796 https://www.cnki.com.cn/Article/CJFDTOTAL-COSE201903014.htmQIAO K, WANG K S, WANG W, et al. Low-cycle fatigue properties of friction stir welding joint of AZ31 magnesium alloy[J]. Rare Metal Materials and Engineering, 2019, 48(3): 788-796 https://www.cnki.com.cn/Article/CJFDTOTAL-COSE201903014.htm [12] 姚宇荃, 王泓, 乙晓伟, 等. 搅拌摩擦焊2124-T851铝合金超低周疲劳特性[J]. 机械科学与技术, 2017, 36(2): 303-307 doi: 10.13433/j.cnki.1003-8728.2017.0224YAO Y Q, WANG H, YI X W, et al, Extremely low cycle fatigue properties of 2124-T851 aluminum alloy fabricated by friction stir welding[J]. Mechanical Science and Technology for Aerospace Engineering, 2017, 36(2): 303-307 (in Chinese) doi: 10.13433/j.cnki.1003-8728.2017.0224 [13] DI S S, YANG X Q, LUAN G H, et al. Comparative study on fatigue properties between AA2024-T4 friction stir welds and base materials[J]. Materials Science and Engineering: A, 2006, 435-436: 389-395 doi: 10.1016/j.msea.2006.07.009 [14] DICKERSON T L, PRZYDATEK J. Fatigue of friction stir welds in aluminium alloys that contain root flaws[J]. International Journal of Fatigue, 2003, 25(12): 1399-1409 doi: 10.1016/S0142-1123(03)00060-4 [15] 杨新岐, 吴铁, 张家龙, 等. 厚板铝合金FSW和MIG焊接接头疲劳性能[J]. 焊接学报, 2012, 33(5): 5-8 https://www.cnki.com.cn/Article/CJFDTOTAL-HJXB201205003.htmYANG X Q, WU T, ZHANG J L, et al. Fatigue properties for FSW and MIG welded joints of thickness plate aluminum alloy[J]. Transactions of the China Welding Institution, 2012, 33(5): 5-8 (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-HJXB201205003.htm [16] FRICKE W. ⅡW Recommendations for the fatigue assessment of welded structures by notch stress analysis: ⅡW-2006-09[M]. Cambridge: Woodheed Publ, 2012 [17] HIGASHIDA Y, BURK J D, LAWRENCE F V. Strain-Controlled Fatigue Behavior of ASTM A36 and A514 Grade F Steels and 5083-0 Aluminum Weld Materials. Welding Research Supplement (AWS), (1978), 344-334 http://www.researchgate.net/publication/321887193_STRAIN-CONTROLLED_FATIGUE_BEHAVIOR_OF_ASTM_A36_AND_A514_GRADE_F_STEELS_AND_5083-0_ALUMINUM_WELD_MATERIALS [18] HOBBACHER A F. Recommendations for fatigue design of welded joints and components[M]//ⅡW Collection. Switzerland: Springer International Publishing, 2016 [19] RAO D, HUBER K, HEERENS J, et al. Asymmetric mechanical properties and tensile behaviour prediction of aluminium alloy 5083 friction stir welding joints[J]. Materials Science and Engineering: A, 2013, 565: 44-50 doi: 10.1016/j.msea.2012.12.014 [20] SMITH K N, WATSON P, TOPPER T H. A stress-train function for the fatigue of metals[J]. Journal of Materials, 1970, 5(4): 767-78 http://ci.nii.ac.jp/naid/10009516116 [21] LASSEN T, RÉCHO N. Fatigue life analysis of welded structures[M]. ISTE Ltd, 2006 [22] MANSON S S. Fatigue: A complex subject-Some simple approximations[J]. Experimental Mechanics, 1965, 5(4): 193-226 doi: 10.1007/BF02321056