Process optimization and microstructural development during superplastic-like forming of AA5083

An advanced sheet forming process was utilized by combining hot drawing and blow forming to establish a fast forming technology. As a continuation of the development in superplastic-like forming, this study dealt with the process optimization and evaluation of post-forming properties. Aluminum alloy 5083 (AA5083) parts with near-net shape were successfully fabricated at 400 °C. Thickness uniformity has been improved by optimizing the mechanical preforming (hot drawing) and adopting a strain-rate-control gas forming (blow forming). Fairly uniform microstructure can be achieved with this forming process. To investigate the microstructural information, the annealed and hot deformed samples were characterized using electron backscatter diffraction technique. Fine grains with high-angle grain boundaries occurred near the elongated grains during hot drawing stage as a result of dynamic recrystallization. Subgrain structure was also examined by characterizing the distribution of grain boundary misorientation angles. Grain growth and subgrain boundary migration were two main microstructural features observed during the gas forming stage.     

Statistical analysis on mechanical properties of friction-stir-welded AA 1050/AA 5083 couples

In this study, the effect of friction-stir welding (FSW) parameters such as spindle rotational speed, traverse speed, and stirrer geometry on mechanical properties of AA 1050/AA 5083 alloy couples were experimentally investigated. Ultimate tensile strength (UTS) and hardness of welded joints were determined for this purpose. The full-factorial experimental design was conducted to obtain the response measurements. Analysis of variance (ANOVA) and main effect plot were used to determine the significant parameters and set the optimal level for each parameter. A linear regression equation was derived to predict each output characteristic. The experimental and predicted values were in a good agreement with a R ² of 0.82 and 0.93 for UTS and hardness, respectively.     

Superplastic-like forming of Ti-6Al-4V alloy

Superplastic forming of titanium alloys is used for producing structural components, since it is an effective way to manufacture complex-shaped parts in a one-step operation. An optimized sheet-forming process has been designed incorporating a non-isothermal heating system to establish a fast forming process. This work sought to expand the advantages of the technology to the forming of Ti-6Al-4V alloy at 800 °C and shorter cycle time. The minimum thicknesses area was found at the outward corners, showing a maximum percent thinning of 54 %. In addition to stress variations, the cracks resulting from hot drawing and the oxidation on the sheet surface are the other reasons leading to thickness reduction. From the oxidization behavior of Ti-6Al-4V alloy, it was revealed that the decrease in forming temperature from 900 to 800 °C significantly reduced the formation rate of oxide film on the sheet surface. The study also showed that the main microstructure evolution of Ti-6Al-4V alloy under these conditions was recrystallization.     

铝合金AA5083超塑性变形力学特性

通过对铝合金AA5083超塑性材料的拉伸试验,分析和讨论了变形温度和应变速率对其延伸率的影响,并得到最佳温度525°C,最佳应变速率1.97×10-4s-1,最大延伸率δ=430%.分别用等应变速率法和速度突变法测定应变速率敏感指数m值.最大m值为0.5.     

Laser Composite Surfacing of Ni-WC Coating on AA5083 for Enhancing Tribomechanical Properties

Laser composite surfacing (LCS) has emerged as an alternative photon-driven manufacturing technology for the fabrication of composite coatings to enhance the tribomechanical properties of various aluminum alloys. The current research presents an analysis on optimization of laser processing parameters for Ni-WC composite coating deposited on AA5083 aluminum alloy in order to improve its tribomechanical properties. To carry out the investigation, Taguchi's optimization method using a standard L₁₆ (3⁴) orthogonal array was employed. Thereafter, the results were analyzed using signal-to-noise (S/N) ratio response analysis and Pareto analysis of variance (ANOVA). Finally, confirmation tests with the best parameter combinations obtained in the optimization process were made to demonstrate the progress made. Results showed that the surface hardness (953 H_v) and roughness (0.81 μm) of coated AA5083 samples was enhanced by 9.27 and 13.14%, respectively. The tribological behavior of LCS samples was investigated using a ball-on-plate tribometer against a counterbody of 440c steel. It was revealed that the wear of the Ni-WC-coated samples improved by around 2.5 times. For lower applied loads, the coating exhibited an abrasive wear mode and a reduction in plastic deformation.     

AA5083管件颗粒介质非均匀内压温热胀形工艺性能解析

基于管件热单向拉伸试验、颗粒介质传压性能试验和外摩擦因数试验,分析了采用温热颗粒介质压力成形工艺时,在非均匀内压下AA5083管材自由胀形区的受力情况,探讨了颗粒介质与管件内壁摩擦作用对管件胀形区壁厚分布和胀形极限的影响。理论分析和工艺试验表明,温热颗粒介质压力成形工艺中颗粒介质与管坯之间存在的有益摩擦有效抑制了管件减薄,提高了管件胀形极限。     

Continuous out-of-plane deformation measurements of AA5083-H116 plates subjected to low-velocity impact loading

An optical system based on structured light and close-range photogrammetry has been developed and is in this study used to continuously measure the full-field out-of-plane deformation of aluminium plates subjected to low-velocity impact loading. During testing, square AA5083-H116 aluminium plates with thickness 5 mm were mounted in a circular frame and impacted by a 30 mm diameter blunt-nose projectile with velocities ranging from 7 to 11 m/s, while the out-of-plane deformations were measured at the opposite side. A fringe pattern was projected onto the rear target surface by a slide projector and the variation in the pattern during penetration was observed by a high-speed camera recording 10,000 images per second. The recorded images were subsequently computer processed to provide full-field topography information of the target surface during deformation. Degradation of measurement data due to impact induced vibration has been evaluated and reduced to a minimum by isolating the optical system from the mechanical experiment. The out-of-plane deformation measurements were compared to non-linear finite element simulations, and the agreement between experimental and predicted results was in general found to be good.     

5083铝合金带吻接FSW接头疲劳强度分析

针对具有吻接缺陷的5083铝合金板搅拌摩擦焊(FSW)对接接头试件,探索了吻接缺陷对搅拌摩擦焊对接接头疲劳强度的影响.使用维氏显微硬度仪测量了试件接头焊缝横截面硬度分布,测试结果显示,硬度值分布大致呈W趋势.采用MTS809疲劳测试机对试件进行疲劳测试,得到了不同吻接深度拉伸式样的名义应力-寿命关系.对疲劳断口进行SE...     

加载路径对AA5083管件热态非金属颗粒介质成形性能的影响

将颗粒介质作为传力介质,应用于铝合金管件内高压热成形工艺。通过热单向拉伸试验建立AA5083板材的本构模型。通过管材热态颗粒介质胀形数值模拟,结合AA5083理论成形极限图的分析,研究了不同加载路径对管件壁厚分布、管端缩料量和主应变曲线的影响规律,并进行了相应的工艺试验验证。研究结果表明,合理匹配初始压头力和管端进给量参数,使预成形管坯在胀形区形成有益皱纹,可为胀形区管坯变形提供聚料作用,从而提高管件成形质量和胀形极限。     

Formability and forming force in incremental sheet forming of AA7075-T6 at different temperatures

Journal of Mechanical Science and Technology - The AA7075-T6 sheet recently received attention, owing to its low weight and strength for use fabricating automotive parts (e.g., body, motor case)....     

Ductile damage prediction of AA 5754 sheet during cold forming condition

Journal of Mechanical Science and Technology - Aluminium sheet parts manufactured by cold-forming processes are subjected to ductile damage due to the plastic deformation. Tool design based on the...     

Prediction of precipitation kinetics during homogenisation and microstructure evolution during and after hot rolling of AA5083

Because previous history of the material such as heat treatment influences the microstructure evolution during hot working, modelling of the microstructure evolution along the process chain is necessary in order to predict the resulting microstructure and hence the mechanical properties. The precipitation kinetics during homogenisation was investigated using the thermodynamic calculation software MatCalc. A physically based internal state variable model was implemented into the commercial Finite Element (FE) analysis package FORGE 2008 for hot rolling simulations of AA5083. The model allowed to predict both the stored deformation energies, i.e. dislocation density, the subgrain structure during hot rolling ,as well as the statically recrystallised volume fraction (SRX) after hot rolling. Two nucleation sites for recrystallised grains were considered to achieve a better understanding of recrystallisation kinetics.To validate the simulation results hot rolling experiments were performed by means of a laboratory mill. The grain structure evolution was analysed by the electron backscatter diffraction (EBSD). The thermo-physical data of the investigated aluminium alloy were determined experimentally.The study shows the applicability of the model to describe the microstructure evolution from casting to the hot rolled product.     

An experimental and numerical study of forming limits of AA5182-O

The International Journal of Advanced Manufacturing Technology - Forming limit curve (FLC) has been applied for evaluating the formability of sheet metal in a standardized way. Various experimental...     

Joinability of different thermoplastic polymers with aluminium AA6082 sheets by mechanical clinching

The International Journal of Advanced Manufacturing Technology - The joinability of different rigid thermoplastic polymers with aluminium AA6082-T6 alloy sheets by mechanical clinching is...     

Electromagnetic superposed forming of large-scale one-dimensional curved AA2524-T3 sheet specimen

This study proposes a methodology for helical mill-grinding of tiny internal threads made of hard brittle materials such as SiCp/Al composites. The methodology uses the helical mill-grinding method incorporating with a diamond form-grinding wheel. A mathematical model is established to predict thread form errors and provide a rational range of wheel parameters, such as variation of tool profile angle Δα and ratio of the wheel diameter to the thread major diameter η. Based on the methodology, a grinding wheel is developed for processing the M2 internal threads in a validation experiment. The study demonstrates that an M2 internal thread made of the SiCp/Al composite of 45% SiC volume fraction is successfully machined in 5 min with pitch error <0.08% and angle error <0.3%. The thread profile on the pitch diameter is within the axial equivalent tolerance zone (0–0.016 mm), which indicates that the thread precision reaches the H4 level.