温度峰值影响6061铝/AZ31B镁异种材料FSW接头成形的规律

以6061-T6铝合金与AZ31B镁合金为研究对象,基于Abaqus软件进行了异种材料搅拌摩擦焊过程的温度场数值模拟,重点分析搅拌针偏置镁侧下的搅拌区温度峰值影响焊缝表面成形的规律。结果表明,当焊接温度峰值高于Al-Mg共晶温度时,搅拌针根部附近区域会出现较明显的黏着现象,其随着焊接速度的降低而加剧,这与焊接温度峰值的升高相关。随着焊接速度的增加,焊缝表面更易避免裂纹缺陷的产生。当搅拌头的转速为1200r/min且焊接速度为40mm/min时,6061铝/AZ31B镁异种材料焊接接头的表面成形良好。     

AZ31-O镁合金和6061-T6铝合金搅拌摩擦焊接头的显微组织和力学性能(英文)

对3 mm厚的AZ31-O镁合金板和6061-T6铝合金板进行异种材料搅拌摩擦焊。实验中搅拌针的旋转速度为600~1400 r/min,前进速度为20~60 mm/min。结果表明,在旋转速度1000 r/min、前进速度40 mm/min的工艺条件下,可以获得无缺陷的焊接接头。组织观察发现搅拌区的晶粒尺寸要比基材区的明显小很多。在搅拌区形成了复杂的金属流动。显微硬度测试表明搅拌区的硬度分别是不均匀的。拉伸实验结果表明,接头的拉伸强度约为基材AZ31镁合金的76%,或6061铝合金的60%。接头拉伸断口SEM形貌观察表明为脆性断裂。     

DP590钢/AA6061-T6铝合金异种金属对接搅拌摩擦焊温度场的数值模拟

为了研究DP590钢和AA6061-T6铝合金异种金属对接搅拌摩擦焊工艺参数对温度场的影响,优化实际焊接时工艺参数的可选择范围,首先建立了异种金属对接搅拌摩擦焊搅拌头摩擦生热的热输入模型,然后运用ABAQUS软件模拟出DP590钢和AA6061-T6铝合金对接搅拌摩擦焊的温度场,研究焊接过程中异种板材温度场的分布规律,最后通过调整焊接参数模拟出接头的温度分布,对比分析搅拌头偏置位置、焊接参数对接头温度场的影响。结果表明:钢铝异种金属对接搅拌摩擦焊焊接过程中的最高温度处位于DP590钢板侧,搅拌针偏置主要影响钢板的温度分布,搅拌头转速是影响焊接接头温度场的主要因素。     

异种铝合金摩擦焊接移动速度和旋转速度的优化(英文)

在摩擦焊接过程中的热效应导致的高模量使铝合金容易变形、强度降低。对船用异种铝合金进行了搅拌摩擦焊接。确定5052-0和6061-T6铝合金在焊接时移动速度和旋转速度的最优条件。得到铝合金最佳焊接条件为移动速度61mm/min和旋转速度1600r/min。     

6061/AZ31B异种材料FSW过程的温度场研究

使用Abaqus软件建立了6061/AZ31B异种材料搅拌摩擦焊的3D有限元模型,对焊接过程的温度场进行了数值模拟。结果表明,以搅拌区为主的高温区形貌在水平面上呈现椭圆形,在横截面上呈碗形。当旋转速度为1100~1300r/min,焊接速度为40mm/min时,焊接温度峰值随旋转速度的增加而提高,其值超过了Al-Mg的共晶点。     

工艺参数对铝镁搅拌摩擦焊焊缝成形质量的影响

工艺参数对铝镁异种材料搅拌摩擦焊接头质量有着重要影响,研究了焊接速度,搅拌头旋转频率,材料放置位置,搅拌头正反转及偏移等工艺参数对7075铝合金与AZ31B热挤压态镁合金异种材料搅拌摩擦焊对接接头成形质量的影响.结果表明,在搅拌针旋转频率为13 r/s,焊接速度为30 mm/min下可获得较好的焊缝成形质量;另外,要获...     

旋转速度对异种厚板铝合金双面搅拌摩擦焊接头力学性能的影响

采用双面搅拌摩擦焊接方法成功实现了15 mm厚板铝合金5052-O/6061-T6的异种搅拌摩擦焊接,研究了搅拌头旋转速度对焊缝力学性能的影响。结果表明:随着搅拌头旋转速度的增加,其焊缝抗拉强度表现出先增加后减少的趋势,伸长率表现出较平稳的趋势;在搅拌头旋转速度为1600 r/min、焊接速度为90 mm/min工艺参数下,获得抗拉强度最大值为216.65 MPa,其伸长率为14.82%。     

6061-T6/7075-T6异种铝合金搅拌摩擦焊接头组织与性能

利用搅拌摩擦焊实现了2 mm厚7075-T6/6061-T6异种铝合金连接,并对材料放置位置和转速对接头成形与组织性能的影响进行了分析. 结果表明,7075-T6铝合金置于前进侧时更有利于焊接过程中材料的迁移行为,焊缝成形及接头性能更优.当焊接速度为150 mm/min、转速为1 000 r/min时,可获得内部无明显缺陷、外观良好的异种铝合金接头;相较于母材,热力影响区的小角度晶界含量增加,焊核区发生动态再结晶,小角度晶界转化为大角度晶界;接头拉伸性能随转速的增加,呈现先增加后减小的趋势.接头的平均抗拉强度和断后伸长率分别达到231 MPa和4.0%. 接头的断裂位置位于6061侧焊核区,与接头硬度最小位置相吻合.     

预热辅助搅拌摩擦焊AA6061-T6和AA7075-T651合金的冶金性能和振声信号变化（英文）

研究AA6061-T6和AA7075-T651合金在搅拌摩擦焊接(FSW)过程中搅拌头形状(圆柱形和方形)、圆柱形搅拌头偏心距(0.5 mm和1mm)和预热(二次加热)对合金冶金性能、振声信号波形变化和接头强度的影响。观察到偏心针能提供良好的流动性和异种金属间的混合,增大搅拌区尺寸,细化搅拌区晶粒尺寸。当轴肩突然插入时,振声信号强度增加;当轴肩到达所需深度时,信号强度减小。与搅拌头插入过程相比,在焊接过程中产生的信号强度更高,这是由于搅拌头在沿焊接轨道运动过程中会不断吸收新的材料。在搅拌针插入前和焊接过程中对工件进行预热可显著影响焊料流动行为和混合形式。与未预热的样品相比,预热后样品中搅拌区的晶粒更粗大,且预热后信号强度明显下降。采用额外加热后,焊接接头的拉伸强度和抗弯强度略有提高。     

6061-T6铝合金与PMMA的搅拌摩擦焊工艺

搅拌摩擦焊在铝合金金属焊接中有着广泛的应用,也可以将金属、聚合物异种材料焊接在一起.文中对铝合金和聚甲基丙烯酸甲酯(PMMA)这2种常用异种材料的焊接进行了研究,将6061-T6铝合金与PMMA薄板进行搅拌摩擦焊试验,验证异种材料搅拌摩擦焊的可行性,选取6061-T6铝合金与PMMA成形较好的焊接接头进行拉伸试验.结果...     

Effect of SiC particles on microstructure and mechanical property of friction stir processed AA6061-T4

Friction stir processing of AA6061-T4 alloy with SiC particles was successfully carried out.SiC particles were uniformly dispersed into an AA6061-T4 matrix.Also SiC particles promoted the grain refinement of the AA6061-T4 matrix by FSP.The mean grain size of the stir zone (SZ) with the SiC particles was obviously smaller than that of the stir zone without the SiC particles.The microhardness of the SZ with the SiC particles reached about HV80 due to the grain refinement and the distribution of the SiC particles.     

Microstructure and mechanical properties of friction stir weld of dissimilar AZ31-O magnesium alloy to 6061-T6 aluminum alloy

Dissimilar friction stir welding between AZ31-O Mg and 6061-T6 Al alloys was investigated. 3 mm thick plates of aluminum and magnesium were used. Friction stir welding operations were performed at different rotation and travel speeds. The rotation speeds varied from 600 to 1400 r/min, and the travel speed varied from 20 to 60 mm/min. Defect-free weld was obtained with a rotation speed of 1000 r/min and travel speed of 40 mm/min. Metallographic studies showed that the grain size in the stir zone is much finer than that in the base metals. Complex flow pattern was formed in the stir zone. Microhardness measurement revealed an uneven distribution in the stir zone. Tensile test results indicated that the tensile strength of the welded specimen is about 76% of AZ31 Mg alloy and 60% of the 6061 Al alloy in tensile strength. SEM fracture surface image of the welded specimen indicated that the welded specimen failed through brittle-mode fracture.     

Development of novel heating tool friction stir spot welding (HT-FSSW) for AZ31 magnesium alloy

In this work, a new heating tool friction stir spot welding (HT-FSSW) process was developed, and its impacts on the microstructure and mechanical properties of the welded AZ31 magnesium alloy joints were investigated by microstructure observation, tensile tests and microhardness tests. An increase in the heating tool temperature resulted in a decrease in the grain size of the stir zone (SZ) and an increase in the grain size of the thermomechanically affected zone (TMAZ). The rising heating tool temperature also aggrandised the bonded zone width and enhanced the tensile shear load strength per unit area of the HT-FSSW welded joints. With an increase in the heating tool temperature, the microhardness of SZ increased while that of the TMAZ decreased. Moreover, the slope of the Hall–Petch relationship between microhardness and grain size of the TMAZ is larger than that of the SZ.     

转速对6061-T6铝合金搅拌摩擦搭接焊接头力学性能的影响(英文)

采用场发射扫描电子显微镜(FE-SEM),研究转速对厚度为5 mm的6061-T6铝合金搅拌摩擦搭接焊接头的宏观和微观组织、硬度、搭接头剪切性能和失效模式的影响。结果表明:在最低的转速度下,上模板和下模板具有十分相似的硬度分布。采用EDX分析发现,焊核区的断裂面中含有Fe的化合物。     

Tensile properties of 6061-T6 friction stir welds and constitutive modelling in transverse and longitudinal orientations

Tensile stress–strain properties of Al alloy 6061-T6 (AA6061-T6) and its butt welds produced by the friction stir welding (FSW) process were characterized in two different loading orientations. AA6061-T6 FS welds were made under three sets of welding conditions. Micro-hardness tests were performed to investigate microstructural evolution during the FSW process. Flat tensile specimens were machined normal and parallel to the weld line. Transvers and longitudinal tensile tests were run on the base material (AA6061-T6) and its FS welds in an Instron testing machine. The strength and ductility (or fracture strain) of the FS welds observed in the transverse orientation were substantially less than those in the longitudinal orientation. Constitutive modelling of uniaxial tensile stress–strain behaviour in both orientations was presented using a rate-independent Ludwik equation. In addition, microstructures of the base material and its FS welds were examined with optical and transmission electron microscopy to discuss the decrease in the flow stress level and the increase in the strain hardening rate of the FS welds.     

Microstructure and mechanical properties of friction stir lap welded Mg/Al joint assisted by stationary shoulder

Using magnesium alloy as upper sheet, 3 mm-thick AZ31 magnesium alloy and 6061 aluminum alloy were joined using friction stir lap welding assisted by stationary shoulder. The effects of tool rotating speed on cross-sections, microstructure and mechanical properties of Mg/Al lap joints were mainly discussed. Results showed that stationary shoulder contributed to joint formation, by which stir zones (SZ) were characterized by big onion rings after welding. Because of the big forging force exerted by stationary shoulder, the upper region of hook was well bonded. SZ showed much higher hardness because of intermetallic compounds (IMCs). The bonding conditions at the base material (BM)/SZ interface at advancing side and the hook region played important roles on joint lap shear properties. The X-ray diffraction pattern analysis revealed that the main IMCs were Al₃Mg₂ and Al₁₂Mg₁₇.     

2024-T3铝合金搅拌摩擦焊接中搅拌头尺寸和搅拌针形状影响的数值模拟

采用完全热力耦合模型研究了搅拌针直径、轴肩直径以及搅拌针锥角对2024-T3铝合金搅拌摩擦焊接过程中热生成、材料变形和能量历史的影响。结果表明：相比搅拌针接触面,轴肩接触面对搅拌摩擦焊接的热生成起主要作用。增加轴肩直径和减小搅拌针直径均能增加焊接温度,但是轴肩尺寸变化的影响更为明显。与6061-T6铝合金的搅拌摩擦焊接过程相比,2024-T3铝合金搅拌摩擦焊接的能量输入明显增加,同时塑性耗散与摩擦耗散的能量比减小。     

搅拌摩擦对接焊6061铝合金的高周疲劳行为

对6061铝合金进行搅拌摩擦对接焊,其焊接工艺参数为：旋转速度600、800、1000、1200 r/min,前进速度80、100 mm/min,探针插入深度1.85 mm。基于搅拌摩擦焊参数计算得到的能量输入结果表明,在输入能量为196～405 kJ的情况下,接头在297～354 kJ的输入能量范围内有最大的抗拉强度。在不同的应力比（R=0.5,0.3,0.1,-0.3,-0.5）下,将高强度、低强度2种焊接头进行疲劳测试。结果表明,对于这2种焊接头,显微组织特征明显影响其疲劳性能,比如搅拌区、热力影响区（TMAZ）和热影响区。从接头的显微组织、裂纹扩展路径和断裂表面观察等方面对其疲劳强度进行讨论。     

Tool design and stir zone grain size in AZ31 friction stir spot welds

Abstract

The influence of tool design and tool rotational speed variations on the torque, energy output, stir zone temperature and average grain size in the stir zones of AZ31 friction stir spot welds was investigated. The average stir zone grain size decreased by ～1 μm in AZ31 friction stir spot welds made using a three-flat/threaded tool design and tool rotational speeds of 2250 and 3000 rev min^?1. However, there was no statistically significant influence of tool design on the average grain sizes in friction stir spot welds made using tool rotational speeds of 1500 and 1000 rev min^?1. There was no evidence of grain growth in the stir zones of AZ31 friction stir spot welds. Similar torque, calculated energy output and stir zone temperature values were found in AZ31 friction stir spot welds made using threaded and three-flat threaded tool designs and tool rotational speeds from 1000 to 3000 rev min^?1.