共查询到18条相似文献,搜索用时 78 毫秒
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对12 mm厚的1060纯铝与T2紫铜进行了双面搅拌摩擦焊接,研究了焊接速度对焊缝成形与接头力学性能的影响。结果表明:在搅拌头转速为600 r/min的条件下,当焊接速度为30~50 mm/min时,焊接速度对接头力学性能影响较小,接头均断裂于铝母材一侧;当焊接速度为30 mm/min时,获得了无缺陷的焊接接头;当焊接速度为40~50 mm/min时,接头出现扁平状小孔洞缺陷,此时,由于搅入焊缝的铜与铝混合形成复合材料结构,增强了焊缝性能,因此,其接头强度仍高于纯铝母材的;当焊接速度超过60 mm/min时,热输入降低引起材料流动不足,在接头内形成贯穿焊缝的孔洞缺陷,使接头承载面积减小,抗拉强度降低。搅拌区中部受到搅拌头两次热力搅拌作用,硬度最高。此外,由于第一道焊缝引起工件变形,在相同下压量的情况下,第二道焊缝相对于第一道焊缝压力略低、热输入较小,使得焊缝底部(即第二道焊缝)的硬度低于焊缝上部(即第一道焊缝)的,且第二道焊缝更易出现孔洞缺陷。综合考虑焊接效率和接头性能,50 mm/min为最优焊接速度,此时接头性能与铝母材的相当,抗拉强度为75.6 MPa,伸长率为26%。 相似文献
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采用搅拌摩擦焊(FSW)完成了3 mm厚TC4钛合金和2A14-T14铝合金的连接,研究了搅拌头偏移对接头的成形及拉伸性能的影响。结果表明在搅拌头向铝合金侧的偏移对接头的最大抗拉强度有显著的影响。接头最大抗拉强度随搅拌头的偏移量的增加逐渐升高。在偏移量为2.0 mm、搅拌头转速从400 r/min增加到700 r/min时,接头的最大抗拉强度逐渐降低。在偏移量为2.5 mm、接头的最大抗拉强度随转速的增加逐渐升高。当在搅拌头转速为700 r/min, 焊接速度为60 mm/min时,所得接头强度最高,约347 MPa,为铝合金母材的83 %。接头的断裂位置和拉伸强度均取决于微观组织和金属间化合物。对于强度最高的接头,由于TiAl相的生成,接头于铝合金侧热影响区发生断裂。 相似文献
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采用搅拌摩擦焊(friction stir welding, FSW),引入厚度为0.05 mm镍箔作为中间层,在焊接速度不变条件下,采用不同转速对厚度为4 mm的6061铝合金和AZ31镁合金进行平板对接,对接头进行系列微观组织表征及力学性能测试,探讨转速对接头中镍颗粒分布状态,金属间化合物(intermetallic compounds, IMCs)种类与分布及接头强度的影响规律. 研究结果表明:与未引入中间层接头相比,引入镍改变了铝/镁异种金属FSW接头焊核区(weld nugget zone, WNZ)中IMCs种类及分布,WNZ存在明显的镁合金与铝合金相间的带状组织,其上分布着絮状Al12Mg17、颗粒状Mg2Ni、层状Al3Mg2及大小不一的镍箔颗粒;随着转速增加,镍箔颗粒分布愈加均匀,Al3Mg2数量相对减少,且脆性Al3Mg2由连续分布逐渐演变为断续分布;当转速为750 r/min时,接头抗拉强度达到最大值,与未引入中间层接头相比,引入镍中间层接头抗拉强度提高了56 MPa,达到镁合金的56.9%. 相似文献
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采用搅拌摩擦焊(FSW)对厚度为4 mm的6061铝合金与AZ31B镁合金进行不同工艺的平板对接试验. 采用光学显微镜(OM)、扫描电镜(SEM)、X射线衍射仪(XRD)及能谱仪(EDS)对接头进行微观组织观察,采用电子万能试验机对接头力学性能进行测试. 结果表明,在接头焊核区(WNZ)中存在着明显的带状组织,带状组织是由插入镁基体中的铝合金条以及弥散分布在条带上的金属间化合物(IMCs)组成;IMCs主要为Al12Mg17和Al3Mg2;铝/镁异种金属FSW接头裂纹形核和扩展均发生在带状组织内;焊接工艺影响带状组织形态和IMCs尺寸及数量;随着转速(n)的增加或焊接速度(v)的降低,带状组织呈弯曲状,长度相对较短且呈不连续分布;当转速(n)过高或焊接速度(v)过低时,带状组织变细,但IMCs数量增多且尺寸变大;铝/镁异种金属FSW接头强度主要取决于带状组织形态和IMCs尺寸及数量. 相似文献
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研究了转速对铝/镁搅拌摩擦焊接头金属间化合物和低熔点共晶的影响,并用电子背散射衍射表征了铝侧和镁侧界面微观结构。结果表明,当采用375 r/min的低转速时,镁侧界面上部出现由Mg固溶体和Al12Mg17相组成的共晶层,平均厚度为38.83 μm。在镁侧界面上部还发现一层厚度为12.3 μm的连续柱状Al3Mg2层,垂直于Al3Mg2层与共晶层的边界。在镁侧界面的中部和底部,只有Al3Mg2层和Al12Mg17层,其厚度沿厚度方向从上到下依次减小。此外,铝侧和镁侧界面的Al3Mg2层具有较高的平均晶粒取向差,这为铝和镁原子间的扩散提供了一条途径。当转速为600 r/min时,Mg固溶体与Al12Mg17相组成的共晶层沿厚度方向分布在镁侧界面上,共晶层厚度较低转速(375 r/min)时显著增加。镁侧界面上部的Al3Mg2层和共晶层的平均厚度分别为32.89和68.92 μm。最后,由转速引起的应变速率对金属间化合物的生长起着重要作用。 相似文献
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铝与钢复合结构是实现载具轻量化的有效途径之一,为了指导铝与钢搅拌摩擦焊接技术的工业应用,必须开展铝与钢异种材料的搅拌摩擦焊接工艺试验。采用填丝搅拌摩擦焊对2.8 mm厚的Q235冷轧钢和2.9 mm厚的5A06铝合金异种金属进行对接焊,分析接头的宏观形貌、微观结构、组织成分、微观硬度和断口形貌。结果表明:C形界面的内凹深度、界面IMC层厚度随旋转速度的增加而增加;大量Al3Ni颗粒呈弥散分布于焊缝中;在旋转速度为420 r/min时,界面IMC层为厚度1.3μm的FeAl相,接头主要断裂于焊核区,断裂模式为韧性断裂,平均抗拉强度为240.3 MPa,正弯角度为19.3°、背弯角度为13.4°;接头显微硬度呈不对称分布,表现出阶跃特征。 相似文献
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研究了搅拌摩擦焊法搭接TA2工业纯钛和T2紫铜。工艺优化实验结果表明:Cu/Ti搭接搅拌摩擦焊工艺窗口较窄,在搅拌头转速800 r/min、焊速20 mm/min以及搅拌头转速900 r/min、焊接速度30 mm/min的焊接工艺参数配比条件下,可获得无缺陷且焊缝表面、搭接界面成形良好的Cu/Ti接头。对搅拌头转速800 r/min、焊速20 mm/min的焊接参数下获得的Cu/Ti接头焊缝进行金相和SEM观察,分析结果表明:搭接界面两侧Cu、Ti宏观流动现象明显,Ti向Cu一侧的塑性材料流动量要明显优于Cu向Ti一侧,且在局部机械混合区呈典型的Cu/Ti相间条带状结构;在搭接界面处形成一层平均厚度约为4.8 μm的扩散过渡层,在过渡层中Cu的扩散速度要大于Ti的扩散速度,Cu/Ti搭接界面形成冶金结合 相似文献
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In this study, fatigue properties and fracture mechanism of dissimilar Al–Mg–Si/Al–Zn–Mg aluminum alloys friction stir welding(FSW) joints were investigated and the effect of the sheet configuration on the fatigue behavior of the FSW joints was also discussed. Results showed that the joints owned better fatigue properties when the Al–Zn–Mg aluminum alloy was placed at the advancing side(AS). At 10~7 cycles, the fatigue strengths of Al–Zn–Mg–AS and Al–Mg–Si–AS joints were, respectively, 105.6 and 90.1 MPa. All joints fractured at the heat-affected zone at the Al–Mg–Si alloy side. Transmission electron microscopy results showed that better fatigue property of the Al–Zn–Mg–AS joint was associated with the bridging effect of the bigger secondary phase particles. 相似文献
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Ryl’kov E. N. Isupov F. Yu. Naumov A. A. Panchenko O. V. Shamshurin A. I. 《Metal Science and Heat Treatment》2019,60(11-12):734-738
Metal Science and Heat Treatment - Friction-stir-welded joints of commercial-purity copper and aluminum alloy AMg5 are studied. The effect of the process parameters on the microstructure and... 相似文献
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The pure Zn foils with different thicknesses(0.02, 0.05, 0.1, 0.2 and 0.3 mm) were selected as interlayers to improve the quality of friction stir lap welding joint of 7075-T6 Al and AZ31 B Mg dissimilar alloys. The effects of the interlayer thickness on joint formation, microstructure and tensile strength were analyzed. The results displayed that the maximum length of the boundary between stir zone(SZ) and thermo-mechanically affected zone in lower plate was obtained by the addition of the Zn interlayer with 0.05 mm thickness. The Mg–Zn intermetallic compounds(IMCs) were discontinuously distributed in the SZ, replacing the continuous Al–Mg IMCs. The size of Mg–Zn IMCs increased with the increase in the thickness of the Zn interlayer. The maximum tensile shear strength of 276 N mm-1 was obtained by the addition of 0.05 mm Zn foil, which increased by 45.6% of that of the joint without the Zn foil addition. 相似文献
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S. A. Khodir M. M. Z. Ahmed Essam Ahmed Shaymaa M. R. Mohamed H. Abdel-Aleem 《Journal of Materials Engineering and Performance》2016,25(11):4637-4648
Types and distribution of intermetallic compound phases and their effects on the mechanical properties of dissimilar Al/Cu friction stir welded joints were investigated. Three different rotation speeds of 1000, 1200 and 1400 rpm were used with two welding speeds of 20 and 50 mm/min. The results show that the microstructures inside the stir zone were greatly affected by the rotation speed. Complex layered structures that containing intermetallic compound phases such as CuAl2, Al4Cu9 were formed in the stir zone. Their amount found to be increased with increasing rotation speed. However, the increasing of the rotation speed slightly lowered the hardness of the stir zone. Many sharp hardness peaks in the stir zones were found as a result of the intermetallic compounds formed, and the highest peaks of 420 Hv were observed at a rotation speed of 1400 rpm. The joints ultimate tensile strength reached a maximum value of 105 MPa at the rotation speed of 1200 rpm and travel speed of 20 mm/min with the joint efficiency ranged between 88 and 96% of the aluminum base metal. At the travel speed of 50 mm/min, the maximum value of the ultimate tensile strength was 96 MPa at rotation speed of 1400 rpm with the joint efficiency ranged between 79 and 90%. The fracture surfaces of tensile test specimens showed no evidence for the effect of the brittle intermetallic compounds in the stir zones on the tensile strength of the joints. 相似文献
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The influences of pin offset on the formation, microstructure and mechanical properties of friction stir welded joint of Ti6 Al4 V and AZ31 B Mg dissimilar alloys were investigated. The results show that sound joints are obtained at different offsets. With the offset decreasing from 2.5 to 2.1 mm, the number of Ti alloy fragments is increased, and the stir zone(SZ) is enlarged and the grains in SZ become coarser. A hook-like structure is formed at the Mg/Ti interface and its length is increased with the decrease in pin offset. The Al element has an enrichment trend at the Ti alloy side near the Mg/Ti interface when the offset is decreased, which is beneficial to the bonding of the interface. An Al-rich layer with a thickness of 3–5μm forms at the offset of 2.1 mm. All the joints fracture at the interface and present a mixed ductile-and-brittle fracture mode. The joint tensile strength is increased with the offset decreasing from 2.5 to 2.1 mm, and the maximum tensile strength of 175 MPa is acquired at the offset of 2.1 mm. 相似文献
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Chai Peng Yang Kang Ji Shude Ai XinXin Lv Zan Song Qi 《JOM Journal of the Minerals, Metals and Materials Society》2019,71(5):1760-1767
JOM - To reduce intermetallic compounds (IMCs), dissimilar Mg/Al alloys were joined by solid-state friction spot welding. No incomplete refilling was observed when Al sheet served as the upper... 相似文献
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Refi ll friction stir spot welding, also known as friction spot welding(FSpW), is a solid-state welding process suitable for spot joining of lightweight materials. Through the eff orts of improving joint quality for similar and dissimilar materials, for example, aluminum and magnesium, this joining technology is well developed. The joining mechanism and process characteristics of FSpW have been widely studied. However, the application of FSpW in industry has not been entirely successful. In this review article, the research of similar and dissimilar material joints, such as, Al/Cu, Al/Ti, Al/Mg and Al/Steel, is summarized. The microstructural features and mechanical properties of the joints, welding tool and the application development are discussed in detail. 相似文献