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6061铝合金搅拌摩擦焊接头组织与性能研究 总被引:1,自引:1,他引:0
采用搅拌摩擦焊方法(FSW)对6 mm厚的6061-T4铝合金板材进行对接,焊后利用光学显微镜(OM)和扫描电镜(SEM)分析、对比了焊接接头和母材的显微组织和断口形貌特征,并测试了其室温拉伸性能和显微硬度。实验结果表明:选择了适合于6061-T4铝合金板材搅拌摩擦焊的工艺参数:焊接时搅拌头旋转速度为1200 r.min-1,工件的进给速度为300 mm.min-1,在此参数下获得了与母材等强度、韧性接近于母材的焊接接头,为此种合金应用于汽车关键零部件提供了可靠的工艺方法。FSW板材接头焊核区的组织和性能明显优于其他区,热影响区是接头最薄弱的部分,焊核区的硬度最高,而热影响区的硬度最低,焊缝金属发生回复再结晶使晶粒细化。断口分析表明,断裂发生在热影响区,由于搅拌头的旋转运动和热量的累积,该区存在晶粒长大、组织粗化现象。对工艺参数的优化实验表明,搅拌头旋转速度与焊接速度对接头性能的影响存在一定的适配关系,通过工艺参数的调整可以有效地控制热影响区的焊缝组织和改善焊接接头的性能。细晶强化是搅拌摩擦焊接头强度与韧性提高的主要原因。 相似文献
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搅拌摩擦焊接残余应力的研究进展 总被引:1,自引:0,他引:1
搅拌摩擦焊(FSW)是一种新型的固态焊接技术。作为一种新技术,还存在着许多问题需要更深入广泛地研究,如材料的流动、温度场、接头的残余应力等。本文介绍了FSW残余应力的试验测量方法和有限元数值模拟方法的研究进展,以及FSW接头残余应力控制技术,分析了接头残余应力的影响因素,揭示了FSW焊接接头残余应力分布的一般规律。 相似文献
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本文对高速列车采用的6005和7005(919)两种铝合金焊接接头微区性能进行了试验研究。对其试验方法和试验结果作了叙述。对铝合金焊接接头微区性能变化规律进行了分析。结果表明,微型剪切试验特别适用于焊接接头的微区性能研究,其测量结果可作为材料及其工艺和设计的评定依据。 相似文献
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《稀有金属》2017,(7)
采用激光焊接方法对2 mm厚喷射成形的7055铝合金进行了焊接实验。通过背散射电子衍射技术(EBSD)、扫描电镜(SEM)、能谱仪(EDS)、透射电镜(TEM)、显微硬度和室温拉伸试验等测试方法对焊接接头的微观组织和力学性能进行了分析。结果表明:7055铝合金激光焊接头热影响区无明显的软化,焊缝显微硬度最低,约为母材的77%,接头的抗拉强度和伸长率分别约为母材的61%和4.1%。热影响区观察到发生了再结晶的等轴晶粒,但晶内可观察到弥散的η'相;熔合线附近形成了晶粒取向随机分布的细小的等轴非枝晶区;焊缝区靠近熔合线为柱状枝晶,靠近焊缝中心为胞状枝晶,晶内无弥散强化相。综上所述,这些区域的微观组织特征揭示了焊接接头的不均匀性,其综合机械性能较母材有所下降,焊缝成为接头的最薄弱环节。 相似文献
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J. J. S. Dilip M. Koilraj V. Sundareswaran G. D. Janaki Ram S. R. Koteswara Rao 《Transactions of the Indian Institute of Metals》2010,63(4):757-764
Fusion welding of dissimilar aluminum alloys is very challenging. In the present work, Al-Cu alloy AA2219-T87 was friction
stir welded to Al-Mg alloy AA5083-H321. Weld microstructures, hardness, and tensile properties were evaluated in as-welded
condition. Microstructural studies revealed that the nugget region was primarily composed of alloy 2219, which was placed
on the advancing side. No significant mixing of the two base materials in the nugget region was observed. Hardness studies
revealed that the lowest hardness in the weldment occurred in the heat-affected zone on alloy 5083 side, where tensile failure
were observed to take place. Tensile tests indicated a joint efficiency of around 90%, which is substantially higher than
what can be achieved with conventional fusion welding. Overall, the results show that satisfactory butt welds can be produced
between AA2219-T87 and Al-Mg alloy AA5083-H321 sheets using friction stir welding. 相似文献
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X. P. Liu R. Lin Peng M. Hofmann S. Johansson Y. D. Wang 《Metallurgical and Materials Transactions A》2011,42(1):89-94
An in-situ neutron diffraction technique was used to investigate the lattice strain distributions and micromechanical behavior in a
friction stir welded (FSW) sheet of AA7475-T761. The neutron diffraction experiments were performed on the spectrometer for
material research, STRESS-SPEC, at FRM II (Garching, Germany). The lattice strain profiles around the weld center were measured
as a function of the applied strain during the tensile loading and unloading. The anisotropic elastic and plastic properties
of the FSW aluminum alloy were simulated by elasto-plastic self-consistent (EPSC) model to predict the anisotropic deformation
behaviors involving the grain-to-grain interactions. Material parameters used for describing the constitutive laws of each
test position were determined from the measured lattice strain distributions for different diffraction hkl planes as well as the macroscopic stress-strain curve of the FSW aluminum alloy. A good agreement between experimental results
and numerical simulations was obtained. The present investigations provided a reliable prediction of the anisotropic micromechanical
behavior of the FSW aluminum alloy during tensile deformation. 相似文献
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Hakan Aydin Mümin Tutar Ali Durmuş Ali Bayram Tayfun Sayaca 《Transactions of the Indian Institute of Metals》2012,65(1):21-30
The present work describes the effect of welding parameters on the tensile properties and fatigue behaviour of 2014-T6 aluminum
alloy joints produced by friction stir welding (FSW). Characterization of the samples has been carried out by means of microstructure,
microhardness, tensile properties and fatigue behaviors. The hardness in the softened weld region decreases with decreasing
the welding speed. Irrespective of the tool rotation speeds, the best tensile and fatigue properties were obtained in the
joints with the welding speed of 80 mm/min. The joint welded with a rotating speed of 1520 rpm at 80 mm/min has given a highest
tensile and fatigue properties. The fatigue behaviors of the joints are almost consistent with the tensile properties, especially
elongations. Higher ductility in FSW joints made the material less sensitive to fatigue. The location of tensile fractures
of the joints is dependent on the welding parameters. On the other hand, the fatigue fracture locations change depending on
the welding parameters and stress range. In addition, a considerable correlation could not be established in between heat
indexes and mechanical properties of FSW 2014-T6 joints under the investigated welding parameters. 相似文献
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V. Fahimpour S. K. Sadrnezhaad F. Karimzadeh 《Metallurgical and Materials Transactions A》2013,44(5):2187-2195
The variation of morphology and mechanical properties of Al6061 automotive aluminum alloy due to friction stir welding (FSW) and gas tungsten arc welding (GTAW) was investigated by optical metallography, scanning electron microscopy, microhardness measurement, X-ray diffraction, tensile testing, and fractography. The center-line dendrite emergence and microhardness reduction in the heat-affected zone were observed in the GTAW process. Although similar microhardness reduction with respect to the base metal was observed in the FSW samples, higher HVs were obtained for the FSW rather than the GTAW process at almost all heat-affected locations. Ultimate tensile strengths of the FSW and the GTAW samples in the transverse direction were ~0.57 and ~0.35 of the base metal, respectively. Post-weld aging improved the strength, but reduced the ductility of the welding. 相似文献
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《Baosteel Technical Research》2010,(Z1):81
FSW and TIG were conducted on 316L stainless steel.Variation during microstructure and properties in joints obtained by different welding methods was studied.The results show that the effect of severe mechanical stirring and intense plastic deformation creat a fine recrystallized grain in the welding joint during FSW.As for TIG,the temperature of welding joint exceeds the melting point of welded material itself.The entire welding process belongs to the solidification of a small molten pool;and the microstructure of the joint takes on a typical casting structure.When the welding parameters were selected appropriately,the average ultimate tensile strength of FSW joints can reach 493 MPa,which is 83.6%of base metal;the average elongation is 52.1%of base metal.The average ultimate tensile strength of TIG joints is 475 MPa, which is 80.5%of base metal;the average elongation is 40.8%of base metal.The tensile test of FSW joints is superior to the TIG joints.The microhardness of FSW joint compared to base metal and TIG joint having a significant improvement,which arel95.5 HV,159.7 HV and 160.7 HV,respectively;grain refinement strengthening plays an important role in enhancing the microhardness.The electrochemical corrosion tests show that the joint of FSW 316L austenitic stainless steel has a good corrosion resistance. 相似文献
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In this article, Welding of AA2219 aluminium alloy using Gas tungsten arc welding process (GTAW) and evaluation of metallurgical, mechanical and corrosion properties of the joints are discussed. The weld samples were subjected to ageing process at the temperature range of 195°C for a period of 5 h to improve the properties. AA2219 aluminium plates of thickness of 25 mm were welded using gas tungsten arc welding (GTAW) process in double V butt joint configuration. The input parameters considered in this work are welding current, voltage and welding speed. Tensile strength and hardness were measured as performance characteristics. The variation in the properties were justified with the help of microstructures. The same procedures were repeated for post weld heat treated samples and a comparison was made between as weld condition and age treated conditions. The post weld heat samples had better tensile strength and hardness values on comparing with the as weld samples. Fracture surface obtained from the tensile tested specimen revealed ductile mode of failure. 相似文献
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The effect of the conditions of friction stir welding (FSW) of 1570C aluminum alloy sheets on the structure and mechanical properties of the welded joints is studied. A recrystallized fine-grained structure with a grain size changing with the rate of welding tool rotation forms in a weld during FSW. As compared to the base metal, the yield strength of the weld metal decreases by 9–22% depending on the rate of welding tool rotation, and the ultimate tensile strength is almost independent of the FSW conditions and accounts for ~90% of the ultimate tensile strength of the base metal. The plasticity of the weld metal is >13% for all rates of welding tool rotation. The microstructure and mechanical properties of the weld zone are discussed. 相似文献