激光定向能量沉积Al-Mg-Sc-Zr修复5083-H112铝合金的组织和性能

激光定向能量沉积增材修复技术具有时间短、效率高、成本低、力学性能好等优点,具有很大的发展潜力。采用Al-7.5Mg-0.3Sc-0.28Zr作为修复材料对轨道交通用5083-H112铝合金进行激光修复实验,得到了致密、无缺陷的修复试样,并对其组织和性能进行研究,探讨了激光修复铝合金的可行性。结果表明,熔合线附近过渡区可划分为修复区、部分熔化区、热影响区和母材。修复区为完全等轴晶,由平均晶粒尺寸为4.95μm的细晶带和18.34μm的粗晶区组成。从修复区到部分熔化区再到热影响区的过渡区域,Al元素含量逐渐升高,Mg元素含量逐渐下降,硬度逐渐下降,修复后母材未被软化。由于激光增材制造技术的快速凝固,在熔合线附近的细晶带有较大的应力集中,由于较小的热输入在部分熔化区、热影响区的残余应力较小。修复试样的屈服强度为(152±2)MPa,为母材的89.4%;抗拉强度为(305±5)MPa,为母材抗拉强度的100%;伸长率为(15.5±0.5)%,为母材的85.2%;断裂发生在强度较弱的母材。高性能的激光修复铝合金是可实现的,具有广泛的应用前景。

Microforming of superplastic 5083 aluminum alloy

The mechanical behavior of superplastic 5083 aluminum alloy during microforming process was investigated by finite element analysis.A micro V-groove die was modeled to analyze the effects of forming time,load and temperature on the microformability of the 5083 aluminum alloy.First,the microformability of the 5083 aluminum alloy was estimated using a microformability index.The simulation results show that the microformability increases with the forming load,time and temperature increasing.Superplasticity of the 5083 aluminum alloy during microforming using the V-groove die was also investigated in terms of the effective strain rate.The results show that the superplasticity of the 5083 aluminum alloy occurs in a specific part of the material for a specific period during the microforming process depending on the forming conditions and the microformability index.

Joint performance of CO_2 laser beam welding 5083-H321 aluminum alloy

Laser beam welding of aluminum alloys is expected to offer good mechanical properties of welded joints. In this experimental work reported, CO2 laser beam autogenoas welding and wire feed welding are conducted on 4 mm thick 5083- H321 aluminum alloy sheets at different welding variables. The mechanical properties and microstructure characteristics of the welds are evaluated through tensile tests, micro-hardness tests, optical microscopy and scanning electron microscopy （SEM）. Experimental results indicate that both the tensile strength and hardness of laser beam welds are affected by the constitution of filler material, except the yield strength. The soften region of laser beam welds is not in the heat-affected zone （ HAZ ）. The tensile fracture of laser beam welded specimens takes place in the weld zone and close to the weld boundary because of different filler materials. Some pores are found on the fracture face, including hydrogen porosities and blow holes, but these pores have no influence on the tensile strength of laser beam welds. Tensile strength values of laser beam welds with filler wire are up to 345.57 MPa, 93% of base material values, and yield strengths of laser beam welds are equivalent to those of base metal （264. 50 MPa）.

Fabrication of anodized superhydrophobic 5083 aluminum alloy surface for marine anti-corrosion and anti-biofouling

Marine corrosion and biofouling seriously affect the service life of marine structural materials,resulting in performance failure,enormous economic loss,and even catastrophic safety accidents.It is worthwhile and desirable to develop high-efficiency strategy for anti-corrosion and anti-biofouling.In this paper,superhydrophobic 5083 aluminum alloy(AA5083)surface with micro-nano hierarchical morphology was fabricated through anodization followed by 1H,1H,2H,2H-perfluorooctyltriethoxysilane(POTS)modification.The surface morphologies,roughness,and chemical compositions were revealed by scanning electron microscopy,atomic force microscopy,and X-ray diffraction.The self-cleaning ability,corrosion resistance and algae adhesion suppression ability of the fabricated surfaces were investigated,indicating an excellent water-proofing,anti-corrosion and anti-biofouling performance.We believe the superhydrophobic creation of metallic materials is expected to have potential applications in marine corrosion and antibiofouling fields.

Corrosion Mechanism of 5083 Aluminum Alloy in Seawater Containing Phosphate

As a material with good corrosion resistance,5083 aluminum alloy has a great application prospect in marine environment.In this work,the corrosion characteristics of 5083 aluminum alloy in seawater containing phosphate were investigated with Potentiodynamic Polarization,Electrochemical Impedance Spectroscopy (EIS),Scanning Electron Microscope (SEM),Energy Dispersive Spectroscopy Analysis (EDSA),X-ray Photoelectron Spectroscopy (XPS) and Laser Confocal Microscope.The results indicated that the effects of phosphate in seawater were two-fold.Firstly,phosphate slightly accelerated the corrosion of 5083 in seawater in the early stage of corrosion.HPO_4~(2-)competed with OH~-in the adsorption process on the alloy surface,which weakened the contact between OH~-and Al~(3+)near the interface of the alloy,and inhibited the formation as well as the self-repair of the passive film,thus accelerating the activation dissolution process.Compared with the natural seawater,the charge transfer resistance of 5083 in the seawater containing phosphate decreased faster during the early stage of corrosion,and the corrosion current density i_(corr) was higher in seawater containing phosphate.On the other hand,the addition of phosphate would not affect the cluster distribution of the second phase of 5083 in seawater,but it changed the composition of the corrosion product layer and had an obvious inhibitory effect on the local corrosion of 5083 in seawater.After 16-day exposure,shallower and more sparsely distributed pits could be observed on the derusted surface of 5083 in the seawater containing phosphate,and the pitting coefficient in the seawater containing phosphate was significantly lower than that in natural seawater.The reduction of pitting tendency could be realized mainly through two ways.First,the HPO_4~(2-)adsorbed on the surface of the passive film in the early stage of corrosion and repeled the corrosive anions such as Cl~-.Second,phosphate participated in the construction of the Ca HPO_4 precipitation film,which acted as a barrier and protection.

Influences of tool plunge speed and tool plunge depth on friction spot joining of AA5454-O aluminum alloy plates with different thicknesses

AA5454-O aluminum alloy plates with the thicknesses of 1.4 and 1.0 mm were friction-spot-joined (FSJed).The plunge speed of the joining tool was changed in a range of 100 500 mm/min under a constant rotation speed of 500 r/min.The plunge depth was ranged from 1.6 mm to 2.2 mm.The tool plunge speed did not make a remarkable effect on the surface appearance and macro-structure of the FSJed zone.The average hardness of the FSJed zone was greater than or equal to that of the base metal.However,there was no remarkable tendency in the average hardness change of the FSJed zone in spite of the variation in the tool plunge speed and tool plunge depth.The increase of the tool plunge depth resulted in the increase of the tensile shear load.However,the change of the tool plunge speed did not lead to the remarkable variation in the tensile shear load of the FSJed plates.It was noteworthy that the FSJed plate exhibited the highest tensile shear load of about 4.0 kN.

Influence of tool plunge depth and welding distance on friction stir lap welding of AA5454-O aluminum alloy plates with different thicknesses

AA5454-O aluminum alloy plates with thicknesses of 1.4 and 1.0 mm were friction-stir-lap-welded (FSLWed).The influences of the tool plunge depth and welding distance on surface appearance,macrostructure and mechanical properties of the FSLWed plates were experimentally investigated.The tensile shear load of the FSLWed plates was compared with that of the adhesive-bonded plates.Defect-free FSLWed zones were successfully obtained in all the tool plunge depths and the welding distances.The FSLWed zones exhibited the relatively smooth surface morphologies.Under all the FSLWed conditions,the FSLWed zone exhibited higher average hardness than the base metal.In addition,the upper plate exhibited a higher average hardness than the lower plate,although there was no special tendency in spite of the change in the tool plunge depth and the welding distance.The maximum tensile shear load of the FSLWed plates was much higher than that of the adhesive-bonded aluminum alloy plate.Especially,under the FSLW condition of the plunge depth of 1.8 mm and the welding distance of 40 mm,the tensile shear load of the FSLWed plate reached a level about 41% greater than that of the adhesive-bonded aluminum alloy plate.In addition,the maximum tensile shear load of the FSLWed plate was increased with the increase of the welding distance.

Significant improvements in mechanical properties of AA5083 aluminum alloy using dual equal channel lateral extrusion

Dual equal channel lateral extrusion (DECLE), as a severe plastic deformation (SPD) process, was employed forimproving the mechanical properties of AA5083 aluminum alloy. Several experiments were conducted to study the influences of theroute type, namely A and B, and pass number on mechanical properties of the material. The process was conducted up to 6 passeswith decreasing process temperature, specifically from 573 to 473 K. Supplementary experiments involving metallography, hardnessand tensile tests were carried out in order to evaluate the effects of the process variables. The hardness measurements exhibitedreasonably uniform distributions within the product with a maximum increase of 64% via a 6-pass operation. The yield and ultimatestrengths also amended 107% and 46%, respectively. These significant improvements were attributed to the severe shear deformationof grains and decreasing pass temperature, which intensified the grain refinement. TEM images showed an average grain sizereduction from 100 μm for the annealed billet to 200 nm after 6 passes of DECLE. Finally, the experimental findings for routes A andB were compared and discussed and some important conclusions were drawn.

5083铝合金搅拌摩擦焊接头拉伸行为研究

目的研究5083铝合金搅拌摩擦焊接(FSW)的组织、力学性能和拉伸应变,分析接头的拉伸行为。方法采用数码相机、光学显微镜、电子扫描显微镜等表征分析方法,对焊缝的表面宏观成形、微观组织、断口形貌进行分析;利用拉伸机、三维数字动态散斑应变测量分析系统和显微维氏硬度计对接头的力学性能和拉伸应变进行测试。结果不同焊接工艺参数下FSW接头的最低抗拉强度为305 MPa,断后延伸率达到了14%以上;焊核区拉伸应变沿板厚方向呈现上高下低和上宽下窄的不均匀梯度分布,发生了较大程度的变形强化,直到拉伸应力达到抗拉强度。断裂失效前300/120接头的最大拉伸应变在晶粒粗大的母材区,500/120和500/200接头的最大拉伸应变则位于晶粒尺寸差异较大的后退侧焊核区与热力影响区交界处。接头拉伸断口宏观上均为45°剪切韧性断裂,微观上均以韧窝韧性断裂为主,而高热输入500/120接头出现脆性断裂特征,其延伸率明显降低。结论高热力耦合输入使铝合金FSW接头薄弱区发生转变,强韧性降低。

Friction stir butt welding of A5052-O aluminum alloy plates

Friction stir butt welding (FSW) between A5052-O aluminum alloy plates with a thickness of 2 mm was performed.The rotation speeds of the welding tool were 2000 and 3000 r/min,respectively.The traverse speed was ranged from 100 mm/min to 900 mm/min.The defect-free welds with the very smooth surface morphology were successfully obtained,except for at the welding condition of 3000 r/min and 100 mm/min.The onion ring structure was observed in the friction-stir-welded zone (SZ) at the condition of 2000 r/min and 100 mm/min.For all the welding conditions,the grain size of the SZ was smaller than that of the base metal,and was decreased with the decrease of the tool rotation speed and with the increase of the tool traverse speed.The stir zone exhibited higher average hardness than the base metal.The decrease of the tool rotation speed and the increase of the tool traverse speed resulted in the increase in the average hardness of the SZ.The tensile strength of the FSWed plates was similar to that of the base metal,except for at the welding condition of 3000 r/min and 100 mm/min.The total elongation of the FSWed plates was lower than that of the base metal.

5083铝合金搅拌摩擦焊缝多区域力学性能研究

对12 mm厚的5083铝合金双轴肩搅拌摩擦焊接头不同区域进行金相组织观察、拉伸试验、硬度测试和疲劳试验,对疲劳试验后的试样断口进行SEM观察。结果表明:焊核区晶粒明显细化,热影响区晶粒粗化,热机影响区晶粒发生严重变形并带有方向性。接头整体硬度近似呈非对称的“W”形分布。从母材到焊核区硬度先减小后增大。母材硬度值最高,焊核区次之。母材、焊核区、热影响区的疲劳寿命差别较大,母材疲劳性能最好,焊核区次之,热影响区最弱。各区的疲劳裂纹源位于疲劳试样的表面,扩展区中可以看到疲劳条带,瞬断区断裂形式均为韧性断裂。

Unified Principal S-N Equation for Friction Stir Welding of 5083 and 6061 Aluminum Alloys

With the popularization of friction stir welding(FSW),5083-H321 and 6061-T6 aluminum alloy materials are widely used during the FSW process.In this study,the fatigue life of friction stir welding with two materials,i.e.,5083-H321 and 6061-T6 aluminum alloy,are studied.Fatigue tests were carried out on the base metal of these two materials as well as on the butt joints and overlapping FSW samples.The principle of the equivalent structural stress method is used to analyze the FSW test data of these two materials.The fatigue resistances of these two materials were com-pared and a unified principal S-N curve equation was fitted.Two key parameters of the unified principal S-N curve obtained by fitting,Cd is 4222.5,and h is 0.2693.A new method for an FSW fatigue life assessment was developed in this study and can be used to calculate the fatigue life of different welding forms with a single S-N curve.Two main fatigue tests of bending and tension were used to verify the unified principal S-N curve equation.The results show that the fatigue life calculated by the unified mean 50%master S-N curve parameters are the closest to the fatigue test results.The reliability,practicability,and generality of the master S-N curve fitting parameters were verified using the test data.The unified principal S-N curve acquired in this study can not only be used in aluminum alloy materials but can also be applied to other materials.

轨道交通车辆用5083铝合金单边角接接头的疲劳性能研究

针对轨道交通车辆常用4 mm厚5083铝合金板材单边角接焊接接头展开疲劳性能研究,求得其单边角接焊接接头的S-N曲线及条件疲劳极限。采用金相显微镜、扫描电镜观察接头微观组织和疲劳断口,分析了其疲劳断裂机理。研究结果表明,5083铝合金角焊缝焊接接头微观组织均匀,无微裂纹。焊缝中心硬度最低,硬度值随焊缝中心距离增大而增大,到达母材后硬度值趋于稳定;单边角接接头立板与底板间的抗拉强度仅为110 MPa,远低于母材的324.5 MPa;在加载107条件下,中值疲劳极限为7.33 MPa,仅为母材强度的2.25%,说明沿立板方向承受交变载荷时疲劳性能较差;疲劳裂纹萌生于焊缝根部,由于焊缝内部存在气孔等缺陷,导致疲劳断口存在多个裂纹源。综上,设计5083铝合金单边角接接头时,立板不应承受交变载荷。

冷轧及退火工艺对5083铝合金薄板组织性能的影响

利用金相显微镜、拉伸试验机、弯曲试验机对5083O铝合金板材在不同冷轧加工率(5%~40%)和不同退火温度(120~280℃)下的微观组织、拉伸力学性能、弯曲性能进行了系统研究。研究结果表明,5083O铝合金板材晶粒为细小均匀的等轴晶。随着冷轧加工率从5%增加至40%,晶粒逐渐被压扁、拉长。冷轧加工率不大于10%的板材折弯性能良好;当冷轧加工率为20%时,弯曲样品外侧出现凹凸不平的颈缩区域;当冷轧加工率增加到30%时,折弯样品出现微裂纹;当加工率增加到40%时,裂纹数量增多、尺寸增大。随着退火温度从120℃增加到280℃,不同冷轧加工率的板材屈服强度和抗拉强度呈单调下降趋势,而且屈服强度的降幅大于抗拉强度的降幅,断后伸长率呈单调增加趋势。当冷轧加工率为20%时,需对板材进行200℃以上的退火处理才能满足折弯性能要求;当冷轧加工率增加至30%和40%时,需要对板材进行240℃以上的退火处理才能满足折弯性能要求。

电池包用5083铝合金断裂失效研究

随着汽车安全法规的逐渐严苛、新能源汽车轻量化趋势的不断深入,电池包安全成为新能源车型安全的核心。文章以主要应用于新能源汽车电池包侧护板的5083铝合金为研究对象,通过铝合金静态拉伸、动态拉伸、静态缺口拉伸、中心孔拉伸、剪切、拉剪等试验获得了铝合金在不同应力状态下的力学性能,采用自研软件建立和标定了材料应变硬化曲线和修正莫尔-库仑(MMC)断裂损伤模型参数,并通过三点弯曲试验和动态穿孔验证了MMC失效模型的合理性。结果表明,本研究中得到的失效模型可以较好地预测5083铝合金断裂失效行为,为新能源汽车电池包的安全性能分析提供了有力的材料数据基础。

Growth and corrosion behaviors of thin anodic alumina membrane on AA5083 Al-Mg alloy in incalescent medium

A self-ordered porous film was fabricated on aluminum alloy in a ternary boric-sulfuric-oxalic acid electrolyte system. By means of voltage–time response, the oxidation process as well as the growth efficiency was studied. Field emission scanning electron microscopy（FE-SEM） was adopted to reveal the morphological and microstructural features of as-fabricated oxide layers. The corrosion protection properties of the films were investigated by electrochemical impedance spectroscopy and potentiodynamic polarization measurements. The results showed that increasing the concentration of the double ionic layer located at the oxide interface could accelerate the film growth rate. The anodic oxidative layer with thickness of 8-9 μm and pore diameter of 10-14 nm maintains the pattern and topography of workpieces, compared with the overall closed film with hierarchical structure. Both samples exhibited much lower corrosion current density after boil water sealing. Meanwhile, a superior stability could be achieved through raising the ambient temperature.

多道次搅拌摩擦加工对5083-O铝合金组织性能的影响

在不同轴肩直径、搅拌头转速和搅拌头行进速度下,对2.7 mm厚5083-O铝合金进行了多道次搅拌摩擦加工(multi-pass friction stir processing),搭接率为100%,共进行3道次搅拌摩擦加工.研究结果表明,加工区由细小的再结晶组织组成;随着加工道次的增加,加工区内部缺陷体积减少,晶粒进一步细化,析出相细化并均匀分布,力学性能提高,加工区最高抗拉强度可达360 MPa,延伸率也优于母材;其中,第二道次加工对材料组织和性能的影响最为明显.

5083-O铝合金管材生产工艺研究

研究了不同冷变形程度、退火温度、保温时间对5083-O铝合金管材组织与性能的影响,确定了退火状态管材的生产工艺及热处理制度。在工业生产条件下使其管材的技术指标达到用户的要求。

5083铝合金GTN损伤参数求解与成形极限预测

GTN(Gurson-Tvergaard-Needleman)损伤模型被广泛用于预测金属的韧性断裂,但损伤参数多且求解困难,限制了其实际应用。以5083铝合金为研究对象,通过扫描电镜观察不同变形阶段拉伸试样的孔洞体积占比确定GTN损伤参数的取值范围;借助中心复合实验设计方法构造拉伸曲线关键变量与GTN损伤参数的响应曲面模型,应用NSGA-II遗传算法优化铝合金板料的损伤参数;将优化后的GTN损伤参数应用于有限元分析中,利用数值模拟方法预测5083铝合金的成形极限图(FLD),并通过Nakazima试验测得铝合金板料的FLD,与数值模拟结果进行对比分析。研究结果表明:GTN损伤模型预测的FLD与实验结果的相对误差在10%以内,且拉压变形区域的预测精度高于双拉变形区域的预测精度。

Influence of blank holder type on drawability of 5182-O aluminum sheet at room temperature

To study the influence of blank holder type on the drawability of 5182-O aluminum sheet at room temperature, the flat blank holder and curved blank holder were employed during the deep drawing process. The microstructures were characterized by optical microscopy （OM）. The results reveal that the limiting drawing ratio （LDR） of 5182-O aluminum alloy sheet is 1.7 using the flat blank holder. The drawn cup have severe earring. Compared with using flat blank holder, the LDR of 5182-O aluminum alloy sheet is enhanced to 2.0 using curved blank holder. In addition, the earring ratio also reduces and flange wrinkling is prevented when the curved blank holder is used. These are due to a more uniform sheet flow in different directions with curved blank holder.