搅拌摩擦对接焊6061铝合金的高周疲劳行为（英文）

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。     

焊接参数对5A06铝合金搅拌摩擦焊接头性能的影响

采用搅拌摩擦焊工艺对10 mm厚的5A06铝合金板进行焊接,研究了搅拌头转速(150～400 r/min)、焊接速度(50～200 mm/min)对接头显微组织、拉伸性能和硬度的影响。结果表明:在试验参数范围内焊接均可获得无宏观缺陷且成形良好的搅拌摩擦焊接头;接头焊核区晶粒细小、组织均匀,热机影响区晶粒相比焊核区的粗大,当搅拌头转速为400 r/min、焊接速度为50 mm/min时,接头焊核区和热机影响区的组织明显粗大;当焊接热输入特征值,即焊接速度与搅拌头转速的比值在0.3～0.5 mm/r时,焊接接头的拉伸性能与母材相当,其抗拉强度最高可达381 MPa,断后伸长率可达25.4%;接头焊核区硬度最高,热影响区硬度最低,当搅拌头转速为250 r/min、焊接速度为100 mm/min时,焊核区硬度较高。     

7075铝合金搅拌摩擦焊研究

使用搅拌摩擦焊对8mm厚的7075-T7351铝合金进行了单道平板对接。结果表明,在工艺参数为搅拌头旋转速度为1180r/min、焊接速度为37.5mm/min时,可获得较好的接头,抗拉强度达到390MPa,是母材强度的78%;7075-T7351铝合金搅拌摩擦焊接头微观组织为典型的搅拌摩擦焊接头组织,焊核区为细小的等轴晶,晶粒大小为6~7μm,母材组织中的强化相在此区域消失;接头显微硬度值分布趋势沿焊缝中心两侧基本对称,热机影响区-热影响区过渡区及焊核区硬度低于母材,是焊件的薄弱环节。     

AZ91D薄板搅拌摩擦焊

实现了厚度为2.2 mm铸造镁合金AZ91D薄板的搅拌摩擦焊和钨极氩弧焊,分析了搅拌摩擦焊工艺参数对焊接接头成形的影响和接头组织变化,考察了搅拌摩擦焊接头的力学性能.在搅拌头旋转速度为1 380 r/min时得到了比较理想的焊接接头,而1 960 r/min的转速过大.接头不同区域所受的机械力和热量不同,显微组织明显不同.搅拌区晶粒细小,显微硬度和强度都有所提高.搅拌摩擦焊接头力学性能与热输入有关;与氩弧焊接头相比,搅拌摩擦焊接接头的性能更好.     

基于正交试验的2024-T4铝合金超声辅助搅拌摩擦焊的研究

采用正交试验研究了超声辅助搅拌摩擦焊工艺参数对1.8 mm厚的2024-T4铝合金板接头组织与力学性能的影响。结果表明:焊接速度对接头抗拉强度的影响最大,而旋转速度和超声频率的作用依次减弱;采用最优参数焊接,即当转速为1600 r/min、焊速为240 mm/min、频率为25 k Hz时,其接头的抗拉强度可达397 MPa,比搅拌摩擦焊强度提高了6%。通过对比焊缝宏观及微观纹理、力学性能、金相组织和显微硬度等,均发现超声搅拌摩擦焊焊缝性能要优于搅拌摩擦焊。     

84 mm厚6082铝合金型材搅拌摩擦焊双面焊工艺研究

采用搅拌摩擦焊双面焊工艺,对84 mm大厚板6082-T4铝合金型材对接接头进行了焊接,获得表面成形美观、光亮、无隧道孔和未熔合缺陷的焊接接头。应用光学显微镜、显微硬度仪及电子拉伸试验机等对搅拌摩擦焊接头组织与性能进行研究。试验结果表明,在焊接旋转速度为400 r/min,焊接速度为150 mm/min的工艺参数条件下,接头的抗拉强度达到217 MPa;接头断裂位置开始于焊缝前进侧热影响区与热力影响区的结合处;接头显微硬度最低值出现在双面焊重合区,为HV54。     

6061铝合金搅拌摩擦焊接头性能研究

采用搅拌摩擦焊对6 mm厚6061-T6铝合金板在不同工艺参数下进行焊接。观察了接头的显微组织,研究了接头室温拉伸性能及晶间腐蚀性能,测试了接头腐蚀前后的显微硬度。结果表明:在搅拌头转速900r/min、焊接速度100 mm/min、焊后缓冷工艺下,可得到性能较好的接头,其抗拉强度可达到母材的74%。接头显微硬度呈现"W"型分布,存在明显的软化区,母材的硬度最高,热影响区的硬度最低。晶间腐蚀最严重的部位发生在焊核区,经腐蚀后接头硬度显著下降。     

6005A-T6铝合金双轴肩搅拌摩擦焊接头疲劳性能分析

通过对3.3 mm厚6005A-T6铝合金型材双轴肩搅拌摩擦焊接头进行疲劳试验，分析型材平行段宽度及厚度对试件疲劳性能的影响；并结合典型参数下焊接接头的宏观成形及其微观组织演变，揭示型材双轴肩搅拌摩擦焊接头的断裂行为.结果表明，典型参数下(转速1 000 r/min、焊接速度100 mm/min、平行段宽度和厚度分别为11.8 mm和3.1 mm)接头的拉伸断裂位置位于后退侧热影响区；型材接头前进侧热力影响区晶粒组织的特征会影响型材疲劳裂纹产生与开动；疲劳断口扫描分析显示断口无明显缺陷，试件疲劳条带的扩展区和瞬断区具有典型的疲劳断裂特征，断裂发生在前进侧热影响区位置.     

铜与铝异质搅拌摩擦焊的工艺研究

采用不同的工艺参数对3 mm厚的T2纯铜板材与5383铝合金板材进行了对接搅拌摩擦焊试验,并对焊接接头的显微组织、拉伸性能和耐腐蚀性能进行了测试与对比分析。结果表明,选择适当的工艺参数,可以实现T2纯铜板材与5383铝合金板材的对接搅拌摩擦焊,搅拌头旋转速度、焊接速度和轴肩压力都会影响接头的拉伸性能和耐腐蚀性能,其优选的工艺参数为:搅拌头旋转速度ω=950 r/min、焊接速度v=140 mm/min、ω/v=6.79、轴肩压力P=8 kN。     

7075铝合金搅拌摩擦焊接头组织与力学性能研究

利用搅拌摩擦焊方法对7075铝合金板进行焊接,探讨了焊接速度和搅拌头旋转速度等焊接工艺参数对焊缝成形及接头力学性能的影响,并对焊接接头的显微组织进行了分析.结果表明:采用搅拌摩擦焊焊接7075铝合金时,焊接接头具有较好抗拉性能.当旋转速度为750r/min、焊接速度为95 mm/min时,焊接接头的强度最高,达到母材抗拉强度(487 MPa)的97.4％,并且其伸长率也较高(为3.1％);当旋转速度为950 r/min、焊接速度为150 mm/min时焊接接头的伸长率最好,为4.7％.总体上看,焊接接头的伸长率和母材相比较低.     

Fatigue properties of friction stir welded butt joint and base metal of MB8 magnesium alloy

The fatigue properties of friction stir welded(FSW) butt joint and base metal of MB8 magnesium alloy were investigated.The comparative fatigue tests were carried out using EHF-EM200K2-070-1A fatigue testing machine for both FSW butt joint and base metal specimens.The fatigue fractures were observed and analyzed using a scanning electron microscope of JSM-6063 LA type.The experimental results show that the fatigue performance of the FSW butt joint of MB8 magnesium alloy is sharply decreased.The conditional fatigue limit(2 × 10~6) of base metal and welded butt joint is about77.44 MPa and 49.91 MPa,respectively.The conditional fatigue limit(2 × 10~6) of the welded butt joint is 64.45%of that of base metal.The main reasons are that the welding can lead to stress concentration in the flash area,tensile welding residual stress in the welded joint(The residual stress value was 30.5 MPa),as well as the grain size is not uniform in the heat-affected zone.The cleavage steps or quasi-cleavage patterns present on the fatigue fracture surface,the fracture type of the FSW butt joint belongs to a brittle fracture.     

Friction stir welding of AZ-91 and AM-Lite magnesium alloys

The objective of this paper was to report the results of butt joint quality of friction stir welding (FSW) of samples of alloys of MgAlZn group. Welding has been carried out with the FSW tool of welding speed ranging from 140 to 355 mm/min. In the stir zone and the surrounding, neither porosity nor cracks have been obtained. Microhardness in the stir zone increased for all welds when compared to the base metals, as a consequence of the high grain refinement and increased precipitations at the grain boundaries. The decrease in plastic properties of metal in these regions is expected. The results show a strong relationship between properties of joints and welding parameters.     

强制冷却搅拌摩擦焊接工艺

搅拌摩擦焊接在工业生产中应用的主要问题之一,是焊接硬化状态材料时接头强度系数较低.简要分析了焊接热对接头强度的影响,提出了在搅拌摩擦焊接过程中进行强制冷却的工艺方法.对比了强制冷却对紫铜搅拌摩擦焊接头表面状况、硬度分布和接头性能的影响,建立了强制冷却搅拌摩擦焊接过程中焊接区温度的近似表达式.结果表明,在紫铜搅拌焊接过程中进行强制冷却,可以降低焊接过程中焊缝及热力影响区变形金属的温度,减小接头软化的程度和范围,提高搅拌摩擦焊接接头的性能.采用转速1 500 r/min、移动速度0.3 mm/s的强制冷却的工艺方法,得到的紫铜搅拌摩擦焊接头抗拉强度达269 MPa.     

铝/铜异种材料搅拌摩擦焊接工艺的优化

搅拌摩擦焊(FSW)是近几年发展较快的新型摩擦焊接技术.国内外研究较多的是铝合金及异种铝合金的搅拌摩擦焊接,但对铝/铜异种搅拌摩擦焊接的研究尚不多见.在此通过大量试验,分别在900-1500 rpm、20-50mm/min范围内调整搅拌旋转速度和焊接速度,优化焊缝的成形质量.结果表明,优化工艺参数可以实现铝/铜异种金属...     

高镁铝合金搅拌摩擦交叉焊接头微观组织与力学性能

为满足大型铝合金船舶壁板的制造需求,对新一代高镁铝合金进行了搅拌摩擦交叉焊接试验. 结果表明,交叉焊接头成形良好,搅拌区晶粒尺寸最小,热力影响区晶粒形态没有明显方向性,与单道搅拌摩擦焊相比,交叉焊接头搅拌区晶粒组织更细. 显微硬度测试结果表明,交叉焊接头显微硬度变化范围较小,前进侧接头软化明显;拉伸试验测试结果表明,交叉焊接头抗拉强度为340 MPa,为母材强度的87%,对比搅拌摩擦焊接头抗拉强度358 MPa略微降低,在热影响区断裂,断裂方式为45°韧性断裂;疲劳裂纹萌生于焊缝底部,在最大应力150 MPa下循环超2 × 106次未断裂,疲劳性能良好,瞬断区断裂方式为韧性断裂.     

焊接速度对5754铝合金FSW接头微观组织和力学性能的影响

对3 mm厚的5754铝合金板材进行搅拌摩擦焊接，研究了搅拌头在转速800 r/min条件下，不同焊接速度(100 ~ 400 mm/min)对搅拌摩擦焊接头微观组织和力学性能的影响. 结果表明，5754铝合金FSW接头横截面形貌呈“盆”形. 随着焊接速度增加，5754铝合金FSW接头的焊核区和轴肩区的面积逐渐减小，而搅拌针区面积先增加后减小. 当焊接速度为300 mm/min时，搅拌针区面积达到最大值6.66 mm2，轴肩区和搅拌针区面积比例为0.97，5754铝合金FSW接头的强度系数达到97.5%，这主要是因为轴肩区和搅拌针区面积相近，增大了焊核区和热影响区界面面积，从而提高了FSW接头强度，拉伸断裂在焊核区以外(热影响区或基材区)，断口为韧性断口. 当焊接速度为400 mm/min时，5754铝合金FSW接头的强度系数为58.8%，拉伸试样均断裂在焊核区，断口为脆性断口.     

An analysis of through-thickness residual stresses in aluminium FSW butt joints

In the paper, the results of a wide experimental campaign on friction stir welding (FSW) of aluminum alloys are reported. The attention was focused on the through-thickness residual stresses that occur on aluminum joints, after the welding process. In detail, using the hole-drilling method the residual stresses distribution in the zone close to the tool shoulder border of the joint advancing side, has been investigated; four different aluminum alloys and three different process conditions have been considered. The experimental analysis has shown that unlike traditional welding processes, the residual stresses are negative in the surface of the examined zone, and increase with depth until values of about 100–150 MPa that occur at a depth of about 0.5–1.0 mm. As expected, the maximum value of the residual stresses induced by the FSW process influences the mechanical behavior of the joint significantly, as it has been observed for the AA6082-T6 aluminum alloy by considering its static and fatigue resistance.Such results corroborate that the hole-drilling method, widely employed in the industrial field due to its simplicity and low cost, can be used for an accurate estimation of the maximum residual stresses that occur in an aluminum butt joint obtained by friction stir welding.     

6061铝合金搅拌摩擦焊工艺

采用搅拌摩擦焊方法对板厚6mm的6061铝合金板在不同参数下进行焊接,研究6061铝合金搅拌摩擦焊工艺以及主要参数对焊缝成形和接头力学性能的影响,观察焊接接头的金相组织,通过硬度分布测试分析焊接接头的力学不均匀性.结果表明:压入量过大或过小时容易造成焊接接头成形差等缺陷,压入量为0.3 mm时可以获得优质的焊缝成形;搅...     

搅拌针端部形状对FSW接头根部金属流动行为的影响

采用不同端部形状的搅拌针对12 mm厚的6061-T4铝合金进行对接焊,观察了匙孔处不同横截面上焊缝形貌,分析了搅拌针端部形状变化对FSW接头根部金属流动行为的影响.结果表明,FSW焊缝区金属沿焊缝厚度方向上的迁移主要受搅拌针表面螺纹影响,而搅拌针端部锥度对接头根部金属的迁移的影响可分为两个方面,一是脱离螺纹作用的金属向下迁移,二是焊核区金属的向上迁移.搅拌针端面直径影响FSW接头未焊透厚度.随搅拌针端面直径增加,搅拌针可焊板材厚度增大.     

Influence of Processing Parameters on Induced Energy, Mechanical and Corrosion Properties of FSW Butt Joint of 7475 AA

Friction stir welding (FSW), a promising solid state joining process invented at TWI in 1991, was used to join 9?mm thick 7475 aluminum alloy which is considered essentially unweldable by fusion processes. In the present work, the process parameters such as tool rotational speed were varied from 300 to 1000?rpm for a travel speed of 50?mm/min and the influence of process parameters in terms of energy input on microstructure, hardness, tensile strength, and the corrosion property of 7475 aluminum joints was evaluated and analyzed. The maximum tensile strength of FSW joints was obtained at rotational speed of 400?rpm and traverse speed of 50?mm/min (59.2?kJ) which attributed maximum stirred zone area and maximum hardness. The maximum corrosion resistance properties of weld in 3.5% NaCl solution, however, were obtained at rotational speed of 1000?rpm and traverse speed of 50?mm/min. Furthermore, for a given weld, stirred zone showed improved corrosion properties than TMAZ.