铝-铜异种金属搅拌摩擦焊接头组织及力学性能（英文）

对3 mm厚的1060工业纯铝和退火纯铜异种金属搅拌摩擦焊进行研究。在搅拌头旋转速度为1050 r/min、焊接速度为30 mm/min时,获得性能良好的铝/铜接头。交替片层结构主要分布于焊核区顶部与铜/焊核区交界附近,促进了铝、铜两种材料的界面扩散及铝和铜之间的冶金键合。然而,界面腐蚀形貌揭示界面内部的弱连接机制,导致拉伸试验中裂纹沿界面区域萌生和扩展,断裂方式为韧-脆混合型断裂。接头的抗拉强度为148 MPa,高于工业纯铝母材的抗拉强度。搅拌摩擦焊强烈塑性变形引起的晶体缺陷和晶粒细化加速原子间的短程扩散,从而促进金属间化合物Al4Cu9和Al2Cu的生成。XRD结果显示,金属间化合物Al4Cu9主要位于铜/焊核区过渡区域。焊核区较高的位错密度和位错环的形成是导致该区域硬度明显升高的主要原因。     

5052/T2搅拌摩擦焊接头的组织及性能

对8 mm厚的5052/T2异种合金进行了搅拌摩擦焊,观察了接头的金相组织,测试了接头的显微硬度、抗拉强度及导电率。结果表明:5052/T2 FSW接头界面铝-铜呈迭层交替分布,部分铜镶入界面形成了"钩子"形貌。焊核区组织呈现"洋葱环"特征,出现金属塑性流线,产生了灰白色Cu-Al金属间化合物。铜侧热机影响区在搅拌针的机械和摩擦热循环的双重作用下出现条弧状组织。铝侧热影响区仅受摩擦热循环的作用,组织较粗大。焊核区硬度值有较大的波动。靠近铜侧的硬度值出现突高,可能是产生的铜-铝金属间化合物所致。接头平均抗拉强度为183 MPa,为5052母材抗拉强度的80.6%,断在铝侧热影响区。5052/T2接头焊核区域的导电率达到了5052母材的92.2%。     

2024铝合金与T2紫铜的搅拌摩擦焊接头组织及力学性能

针对板厚均为3 mm的2024铝合金和T2紫铜异种金属进行了搅拌摩擦焊接。采用光学显微镜、扫描电镜和透射电镜对接头组织和铝-铜界面进行观察分析,并进行了显微硬度和拉伸性能测试。结果表明,接头表面成形优异,无宏观缺陷,焊核区形成了明显的洋葱环结构,洋葱环由层片状铝和颗粒形式分布的铜组成;在铝-铜界面形成了一层厚度约0. 98μm的金属间化合物层。在转速为800 r/min、焊接速度为50 mm/min的焊接参数下得到了力学性能优异的接头,接头平均抗拉强度为158 MPa,强度与母材铜相当,平均断后伸长率为10%,为母材铝的87%,拉伸断裂于铜侧母材,断裂方式为韧性断裂。     

纯铜/1350铝合金异种板材搅拌摩擦焊接头的组织与性能(英文)

研究3mm厚的纯铜/1350铝合金异种合金板材的搅拌摩擦焊工艺。通过搅拌头偏置技术,将搅拌头的大部分插入铝合金一侧,在旋转速度和焊接速度分别为1000r/min和80mm/min的条件下,获得无缺陷的接头。在焊核区形成复杂的微观组织中,可以观察到旋涡状花样和层状组织。焊核区没有金属间化合物生成。硬度分布曲线表明,焊核区纯铜一侧的硬度高于1350铝合金一侧的硬度,且焊核区底部的硬度高于其它部分的。接头的抗拉强度和伸长率分别为152MPa和6.3%。断口观察表明,接头断口既存在韧性断裂区域,也存在脆性断裂区域,为混合型断裂。     

1060铝/AZ31镁合金异种金属搅拌摩擦搭接焊组织与力学性能研究

采用搅拌摩擦搭接焊对1060铝和AZ31镁合金异种金属进行焊接试验,利用三维表面形貌仪、光学显微镜研究了接头组织形貌,采用显微硬度仪、电子万能试验机和扫描电子显微镜研究了接头力学性能和断口形貌。结果表明:焊接参数对焊缝表面形貌影响显著,在1500 r/min,50 mm/min时,焊缝表面形成均匀弧纹。在1000 r/min,70mm/min时焊核区及焊缝界面处晶粒经动态再结晶后细化,随转速/焊速比增加,焊核区金属间化合物含量增加。显微硬度结果表明镁合金侧、铝侧和界面处接头显微硬度有相同的变化趋势,焊核区硬度明显高于铝镁母材区域。断口形貌观察结果表明,1060铝/AZ31镁合金异种金属搅拌摩擦搭接焊断裂模式为脆性断裂,接头拉剪性能在2000 r/min,30mm/min时最差,仅为1750N,这可能与焊缝内金属间化合物的增加有关。     

16mm厚T2铜搅拌摩擦焊组织及接头力学性能分析

选用转速300 r/min、焊速30 mm/min的工艺参数对16 mm厚的T2紫铜厚板进行搅拌摩擦焊接,并对其焊接接头的微观组织、力学性能进行了分析。结果表明,焊核区晶粒尺寸比母材细小,其平均硬度为73 HV,稍高于母材,热影响区和热机影响区硬度较低;焊接接头的抗拉强度为229 MPa,是母材的97%,试样断裂的位置均在前进侧热影响区。X射线衍射结果表明,焊接接头只有Cu,无氧化物和其它金属间化合物产生。     

搅拌摩擦焊含铜嵌入板的6061-T6铝合金(Al/Cu/Al)的显微组织和力学性能（英文）

将两块6061-T6板中间嵌入一块纯铜板(Al/Cu/Al),利用搅拌摩擦焊(FSW)技术焊合,研究铜板插入对焊接接头性能的影响,并与无铜板的搅拌摩擦焊AA 6061(Al/Al)的研究结果进行比较。用光学显微镜和扫描电镜观察焊接样品的显微组织,用X射线衍射分析Al/Cu/Al样品的相组成。在转速为1000 r/min和焊接速度为25 mm/min条件下观察到Al/Cu/Al焊接接头无缺陷。焊核区的显微组织观察结果显示类似复合物结构的形成促进了铝和铜的冶金结合。XRD结果显示形成了金属间化合物(IMCs),如Al_4Cu_9和Al_2Cu。由于其更高的位错密度,有Cu板的焊接样品的硬度较高,且IMCs存在的区域其硬度值明显更高。由于铝和铜之间更强的冶金结合,有铜板的焊接接头的极限抗拉强度比无铜板的接头更高。     

旋转速度对铝/钢填丝搅拌摩擦焊接头性能的影响

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。     

焊速对铝铜复合板搅拌摩擦焊接接头的影响

采用搅拌摩擦焊接（friction stir welded, FSW）对铝铜层状复合板进行了焊接,研究了焊接速度对焊接接头组织与性能的影响。结果表明,铝铜复合板搅拌摩擦焊接接头在焊缝区域内铝铜金属呈层状分布,随焊接速度增大,焊核区铝与铜晶粒尺寸逐渐减小。在焊接速度为95 mm/min时,铜层接头平均显微硬度达到88 HV0.2,为铜母材的71.96%。在焊接速度为47.5 mm/min时,铝层接头平均硬度可达到35 HV0.2,高于铝母材显微硬度,并且焊接接头的抗拉强度为115.22 MPa。随着焊接速度的增大,抗拉强度和伸长率降低,拉伸试样断口微观形貌以解理断裂为主。     

焊接速度对铝铜复合板搅拌摩擦焊接接头的影响

采用搅拌摩擦焊接(friction stir welded,FSW)对铝铜层状复合板进行了焊接,研究了焊接速度对焊接接头组织与性能的影响。结果表明,铝铜复合板搅拌摩擦焊接接头在焊缝区域内铝铜金属呈层状分布,随焊接速度增大,焊核区铝与铜晶粒尺寸逐渐减小。在焊接速度为95 mm/min时,铜层接头平均显微硬度达到88 HV0.2,为铜母材的71.96%。在焊接速度为47.5 mm/min时,铝层接头平均硬度可达到35 HV0.2,高于铝母材显微硬度,并且焊接接头的抗拉强度为115.22 MPa。随着焊接速度的增大,抗拉强度和伸长率降低,拉伸试样断口微观形貌以解理断裂为主。     

Dissimilar Joining of Pure Copper to Aluminum Alloy via Friction Stir Welding

In this study, the dissimilar friction stir welding(FSW) butt joints between aluminum alloy 5754-H114 and commercially pure copper were investigated. The thickness of welded plates was 4 mm and the aluminum plate was placed on the advancing side. In order to obtain a suitable flow and a better material mixing, a 1-mm offset was considered for the aluminum plate, toward the butt centerline. For investigating the microstructure and mechanical properties of FSWed joints, optical microscopy and mechanical tests(i.e., uniaxial tensile test and microhardness) were used, respectively.Furthermore, the analysis of intermetallic compounds and fracture surface was examined by scanning electron microscopy and X-ray diffraction. The effect of heat generation on the mechanical properties and microstructure of the FSWed joints was investigated. The results showed that there is an optimum amount of heat input. The intermetallic compounds formed in FSWed joints were Al4Cu9 and Al2Cu. The best results were found in joints with 1000 rpm rotational speed and100 mm/min travel speed. The tensile strength was found as 219 MPa, which reached 84% of the aluminum base strength.Moreover, maximum value of the microhardness of the stir zone(SZ) was attained as about 120 HV, which was greatly depended on the grain size, intermetallic compounds and copper pieces in SZ.     

Effect of Intermetallic Compound Phases on the Mechanical Properties of the Dissimilar Al/Cu Friction Stir Welded Joints

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.     

Preparation of bimetallic nano-composite by dissimilar friction stir welding of copper to aluminum alloy

Butt friction stir welding between pure copper and AA5754 alloy was carried out. Reinforcing SiC nano- particles were utilized in friction stir welded (FSW) joints to decline the harmful effects of intermetallic compounds. Tensile tests, micro-hardness experiments, scanning electron microscopy and X-ray diffraction analysis were applied to studying the properties of welded joints. The joints with a travel speed of 50 mm/min and a rotation speed of 1000 r/min showed the best results. The presence of nano-sized SiC particles reduced the grain size of aluminum and copper in the stir zone (SZ) from 38.3 and 12.4 μm to 12.9 and 5.1 μm, respectively. The tensile strength of the joint in the presence of reinforcing SiC nano-particles was ~240 MPa, which is ～90% of that for the aluminum base. Furthermore, the highest microhardness of the weld zone was significantly increased from HV 160 to HV 320 upon the addition of SiC nano-particles. The results also showed that raising the heat generation in FSW joints increased the amount of Al₄Cu₉ and Al₂Cu intermetallic compounds.     

搅拌头偏移对Ti/Al异种金属搅拌摩擦焊接头成形及拉伸强度的影响

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。     

Microstructural characterization and mechanical properties of aluminum 6061-T6 plates welded with copper insert plate (Al/Cu/Al) using friction stir welding

Friction stir welding was used to join two aluminum 6061-T6 plates with an insert of a pure copper plate (Al/Cu/Al), and then the influence of the copper insert on the joint performance was studied. The dissimilar welding results were also compared with AA 6061 friction stir welds produced without copper insert (Al/Al). Optical and scanning electron microscopes were used for the microstructural observations of the welded samples. X-ray diffraction analysis was used to analyze phase component of the Al/Cu/Al specimen. A defect-free joint was observed for the Al/Cu/Al joint at a rotational speed of 950 r/min and a welding speed of 50 mm/min. Microstructural observation of the weld nugget zone (WNZ) demonstrates the formation of composite-like structure which promotes metallurgical bonding of aluminum and copper. XRD results show the formation of intermetallic compounds (IMCs), such as Al₄Cu₉ and Al₂Cu. Furthermore, it was observed that the hardness of the weld with the Cu insert plate is higher than that of other samples due to more dislocation density and a distinct rise in hardness values was observed due to the presence of IMCs. The ultimate tensile strength of the joint with copper insert plate is higher than that of the other sample due to the strong metallurgical bonding between Al and Cu.     

焊接速度对6005A-T6铝合金双轴肩搅拌摩擦焊接头力学性能的影响

文中研究了转速和热输入特征值WP一定两种条件下焊接速度对6005A-T6铝合金双轴肩搅拌摩擦焊接头力学性能的影响. 结果表明,转速一定时,接头抗拉强度随焊接速度的增加呈先增大后减小的趋势;热输入特征值WP一定时,随着焊接速度的增加,接头的抗拉强度持续减小;接头呈现出三种断裂方式,分别为发生于热影响区的Ⅰ型断裂、发生于焊核区的Ⅱ型断裂和发生于热力影响区的Ⅲ型断裂;Ⅰ型断裂和Ⅱ型断裂为韧性断裂;Ⅲ型断裂为包含韧性断裂和脆性断裂的混合型断裂;接头拉伸断裂位置并非总出现在硬度最低处;焊接速度小于1 000 mm/min时,WP ≤ 1有利于提高接头力学性能,而焊接速度大于1 000 mm/min时,WP > 1更有利于提高接头力学性能.     

7050铝合金搅拌摩擦焊接头微观组织及力学性能分析

采用搅拌摩擦焊焊接厚12 mm的7050铝合金,分析接头的微观组织和力学性能。研究结果表明,焊核区由于热循环作用形成细小的等轴再结晶组织;热机影响区受机械和热的双重作用组织发生了较大程度的变形,在热循环的作用下发生回复反应;热影响区仅受热循环的作用,组织稍微有粗化现象。力学试验表明:旋转速度400r/min、焊接速度180mm/min时,接头的抗拉强度可以达到391 MPa,为母材的77%;焊接速度200 mm/min,旋转速度450 r/min时,接头的抗拉强度可以达到376 MPa,为母材的74%。断口形貌分析显示,接头断裂模式为穿晶和沿晶混合型断裂。     

旋转速度对镁/铜异种金属搅拌摩擦焊接头成形及拉伸性能的影响

保持95 mm/min焊接速度不变的条件下,通过改变旋转速度研究其对镁/铜异种金属搅拌摩擦焊接头成形和力学性能的影响。结果表明:采用750 r/min搅拌头旋转速度焊接时,焊缝表面出现起皮现象;焊核区底部形成明显的隧道槽缺陷。适当增加搅拌头旋转速度至950 r/min时,焊缝表面变得更光滑;混合区尺寸增大;内部隧道槽缺陷消失;该混合区主要由被搅碎的Mg、Cu合金和少量新生成的Mg₂Cu金属间化合物组成;接头的抗拉性能最好,抗拉强度达81.7 MPa;但是,继续增大搅拌头旋转速度至1180 r/min时,不利于接头成形,混合区底部有细小的孔洞缺陷产生。     

焊接参数对7A04铝合金搅拌摩擦焊接头组织与力学性能的影响

采用不同的焊接参数对3 mm厚7A04铝合金板进行焊接,并对接头的组织、沉淀相、力学性能及断口形貌进行了分析. 结果表明,焊核区组织发生动态再结晶,形成细小的等轴晶粒,热影响区晶粒发生明显粗化. TEM分析结果显示,经搅拌摩擦焊后,焊核区部分沉淀相溶解. 焊核区晶粒尺寸随焊接速度增大而减小. 当焊接速度为120 mm/min,旋转速度为800 r/min时,接头强度达到最大值 454.2 MPa,为母材的95%,断后伸长率为3.97%,为母材的70%. 硬度测试显示搅拌摩擦焊接头发生软化,焊缝区域硬度低于母材,硬度值最低点出现在热影响区;拉伸断口形貌SEM图像表明接头断裂方式为韧性和脆性混合型断裂.