Formability and cavitation behavior of superplastic AA5083 aluminum alloy under biaxial tension

The superplastic forming potential of two fine-grained 5083 aluminum alloys were studied under biaxial tension using a pneumatic bulge test. Experiments were performed at temperatures ranging from 475 to 525 ℃ with three different strain paths ranging from equi-biaxial to approaching plane strain. The shape of the forming limited diagram（FLD） is found to be significantly different from FLDs commonly used in room temperature stamping. The effects of temperature on final thickness distribution, dome height and cavitation were investigated for the case of equi-biaxial stretching. Increasing temperature in free bulge forming can improve the thickness distribution of final parts but have no significant effect on dome height. The results indicate that determination of forming limits in SPF cannot be represented with a simple FLD and additional metrics such as external thinning and internal cavitation needed to determine the SPF potential of a material.     

AA5083铝合金在海水中的腐蚀行为研究

采用电化学工作站研究了AA5083铝合金在海水中的极化曲线、点蚀电位、交流阻抗等性能,通过高分辨率数码显微镜、扫描电镜等表征手段对AA5083铝合金腐蚀前后的表面形貌进行了研究。研究结果表明:AA5083铝合金在静态海水中的腐蚀以点腐蚀为主,浸泡初期阻抗由容抗和感抗组成,腐蚀电位随着浸泡时间的延长不断负移,耐腐蚀性降低,点腐蚀坑越来越多,并且点腐蚀坑不断增大加深,在试板表面中间区域形成半球状点腐蚀坑,腐蚀达到一定程度后,出现Warburg阻抗,腐蚀电位逐渐稳定在-0.58V。     

搅拌摩擦加工参数对5083铝合金组织性能的影响

采用搅拌摩擦加工方法对不同焊接参数下的退火态5083铝合金的组织和性能进行研究.通过显微硬度实验研究了硬度在前进侧和后退侧以及加工区上下部分的分布规律;通过金相观察研究了加工区表面带状纹理和腐蚀后观察到的弧纹之间的关系.对母材和加工区用扫描电镜观察了析出相的形貌、尺寸及分布规律.结果表明:高硬度区宽度随着轴肩直径的增大而增大,随着转速和焊速之比(ω/ν)的增加而增大,硬度在前进侧(AS)和后退侧(RS)的分布是不均匀的;从母材到加工区硬度逐渐上升,RS侧的上升速度约为AS侧的一半.     

Ti-45Al-7Nb-2V-2Cr涂层与TA2钛合金电偶腐蚀行为

采用超音速微粒沉积技术在5083铝合金表面制备γ-TiAl基Ti-45Al-7Nb-2V-2Cr合金耐蚀防护涂层,实现γ-TiAl基涂层的原态制备,并对涂层微观结构及电化学性能进行研究。结果表明：在涂层中的Al、V元素富集区,喷涂颗粒发生显著的塑性变形,有利于TiAl合金颗粒的沉积成形;通过在5083铝合金表面制备TiAl合金防护涂层可使其与TA2钛合金的接触腐蚀电流由16.2μA降为0.191μA,接触腐蚀敏感性由E级降到A级,喷涂件可与TA2钛合金直接接触使用,解决了铝合金与钛合金的接触腐蚀防护问题。     

5083铝合金大规格可调结晶器640 mm×1800～2100 mm扁锭铸造工艺的研究

针对大规格可调结晶器640mm×1800～2100mm 5083合金铸造工艺中存在的渣裂、镁成分超标、热裂、褶皱裂纹、锭尾塌陷裂纹及角部撕裂等缺陷分析了原因,并通过试验研究优化了工艺参数。     

LNG全容罐5083铝合金吊顶焊接施工技术

在LNG全容罐建造过程中,铝合金吊顶和拱顶是在混凝土外罐内底部施工,完成后整体气吹顶升至罐顶位置固定.5083铝合金吊顶属于4.76mm的铝板搭接拼焊而成,主要起保温绝热作用,焊接采用手工钨极氩弧焊来完成,在焊接过程中,需要采用合理的焊接顺序和措施来减少残余应力和变形.     

Corrosion protection of aluminum alloy by epoxy coatings containing polyaniline modified graphene additives

In the study, polyaniline/reduced‐graphene oxide (PANI‐RGO) composites, fabricated by loading 2, 5, and 8wt% graphene oxide, was prepared by in‐situ emulsion polymerization and reduction. They are characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, and scanning electron microscopy. Epoxy coatings adding PANI and PANI‐RGO composites were coated on the surface of AA5083 Al alloy. The anticorrosion performance of the coatings is measured by electrochemical impedance spectroscopy and potentiodynamic polarization curve in 3.5wt% NaCl solution. The results demonstrate that the epoxy/PANI‐RGO coating exhibits a better protection against AA5083 alloy corrosion compared with the epoxy/PANI coating. Enhancement of the passivation performance of PANI was obtained by the addition of RGO into epoxy/PANI coating system.     

Study and evaluation of abrasive water jet turning process performance on AA5083

In this study, the effect of processing parameters on surface roughness and macro surface characteristics was analyzed during the machining of Ø30 mm and 300 mm aluminum alloy AA5083 abrasive water jets. As the processing parameters (up to 10 mm min⁻¹, 15 mm min⁻¹, 20 mm min⁻¹ and 25 mm min⁻¹), abrasive flow rate (50 g min⁻¹, 150 g min⁻¹, 250 g min⁻¹ and 350 g min⁻¹), the lathe chuck rotational speed (25 min⁻¹, 50 min⁻¹, 75 min⁻¹ and 100 min⁻¹) and the nozzle approach distance (2 mm, 5 mm, 8 mm and 11 mm) were used in experiments. In experimental studies, the pump pressure (360 MPa) was used as a constant, in the form of an abrasive Garnet (100 mesh), and the nozzle diameter as 0.76 mm. According to the findings, the best results in terms of surface roughness were obtained as a result of turning speed and abrasive flow rate. When the macro surface characteristics were examined, it was found that the lathe chuck rotational speed increased, the rate of nozzle progression was low, the rate of abrasive flow was high and the nozzle approach distance was lower and the smoother surfaces were obtained.     

Effect of anodizing on galvanic corrosion behavior of T300 CFRP/5083P-O Al bolted joints

T300 carbon fiber reinforced polymer (CFRP) and 5083P-O aluminum (5083P-O Al) alloy bolted joints have been used in high-speed trains due to the advantages of light weight and high strength. However, high potential difference between the CFRP and 5083P-O Al will induce galvanic corrosion and result in accelerating corrosion rate of 5083P-O Al, which is a potential risk for its engineering applications. In this work, combination with the electrochemical analysis, surface and cross-section corrosive morphologies analysis, the galvanic corrosion behavior between CFRP/5083P-O Al bolted joints with and without anodizing in 3.5 wt.% NaCl spray was investigated. Results indicated that severe corrosion occurred on unanodized 5083P-O Al in the coupled regions of the CFRP/5083P-O Al bolted joint due to galvanic corrosion. With the content of sulfuric acid increasing, the thickness of each Al₂O₃ layer and atomic oxygen content increases significantly. 5083P-O Al anodized by the 135 g/L H₂SO₄ + 8 g/L H₃BO₃ mixed solution had the favorable Al₂O₃ film, which increased the resistance of 5083P-O Al by roughly three orders of magnitude, effectively improving the corrosion resistance of 5083P-O Al.     

Experimental and numerical assessment of energy absorption capacity of thin-walled Al 5083 tube produced by PTCAP process

The energy absorption capacity of the Al5083 thin-walled tube produced by parallel tubular angular pressing (PTCAP) process was evaluated. Also, microstructure, mechanical properties, and anisotropy coefficients were studied in the peripheral and axial directions. Results showed that values of energy absorption decreased with processing pass increasing and the values for the unprocessed, first and second passes were obtained to be 167, 161.4 and 160.7 J, respectively. The differences between the simulation results for the energy absorption values and their experimental values for the unprocessed, the first and the second PTCAP passes samples are about 5%, 10%, and 13%, respectively. The energy absorption capacity was related to the anisotropy coefficient and microstructure. The results demonstrated that grain refinement occurred and ultimate tensile strength (UTS) and microhardness after the first and second PTCAP passes were enhanced, while the increase rate in the first pass was much severer. Also, by applying PTCAP, the deformation modes were altered, such that the deformation mode of the annealed tube was quite symmetrical and circular while for the first and second passes there have been triple and double lobes diamond. The results of the numerical simulation for the deformation mode of the annealed and PTCAPed tubes were consistent with the experimental results. The deformation mode of tubes is dependent on their mechanical properties and variation of the mechanical properties during PTCAP process.