高性能纳米晶Al-Mg合金的研究进展

本文介绍了国外有关纳米晶Al-Mg合金的研究进展。传统的Al-Mg合金经纳米化后强度得到明显提升,但塑性普遍较低。国外提出了多种思路方法(包括组织优化、成分优化等)对纳米晶Al-Mg合金的强塑性进行优化,使纳米晶Al-Mg合金的强度和塑性得到匹配,研制出了高性能的Al-Mg合金。     

球磨CeMg12+100%Ni合金热力学及电化学贮氢性能

用球磨工艺制备CeMg12+100%Ni电极合金,研究了球磨工艺对合金结构及电化学性能的影响。结果表明球磨CeMg12+100%Ni合金具有非晶纳米晶结构,由Mg2Ni相以及Ni相组成,其含量随球磨时间的延长而增加,这在一定程度上改善了合金的电化学放电性能。球磨非晶纳米晶具有较好的结构稳定性,在吸氢后形成的氢化物相仍保持非晶纳米晶尺度,这有利于降低氢化物的热稳定性,改善电化学放电性能。     

改善Al-Mg合金流动性及力学性能的新方法

目的改善Al-Mg合金的流动性和组织性能。方法向Al-Mg合金中加入含有掺杂型Ti Cx的Al-Ti-C-B晶种合金(简称Al-Ti-C-B),借助其对Al-Mg合金枝晶大小及形貌调控,研究其对Al-Mg合金流动性和组织性能的影响,并与传统的Al-Ti-B中间合金细化剂进行对比。结果加入Al-Ti-C-B后Al-Mg合金的流动性和力学性能均高于Al-Ti-B,螺旋流动性试样长度由692 mm提高到937 mm,提高了约35.4%;Al-Mg合金的拉伸强度分别由192 MPa提高至216 MPa,伸长率由2.1%提高至4.1%,分别提高了12.5%和95.2%。结论借助Al-Ti-C-B及其晶种技术能够实现对Al-Mg合金流动性和力学性能的同步提升。     

复合微合金化对Al-Mg合金组织与性能的影响

研究了Sc和Ti复合微合金化对Al-Mg合金显微组织与拉伸性能的影响.结果表明:Sc和Ti复合微合金化可以显著提高Al-Mg合金的强度,并可细化铸态合金的晶粒组织.微量Sc和Ti的加入可使合金中形成大量细小弥散的球形Al3(Ti,Sc)粒子,这些Al3(Ti,Sc)粒子对位错和亚晶界具有强烈地钉扎作用,因而能强烈抑制合金的再结晶.Sc和Ti复合微合金化的Al-Mg合金的强化作用主要来源于Al3(Ti,Sc)粒子的析出强化和亚结构强化以及细晶强化.     

高能球磨Mg-Zr-Ni合金组织演变

为了改善Mg-Ni合金的电化学性能,采用高能球磨技术合成了Mg-Zr-Ni储氢合金,通过改变球磨条件和添加合金元素Zr,利用XRD物相分析和电化学测量技术,研究了Mg-Ni合金的组织演变过程及其对电化学容量的影响.结果表明,高能球磨Mg-Ni和Mg-Zr-Ni合金都经历了非晶态向纳米晶态的转变过程,用少量Zr替代部分Mg后,促进了高能球磨Mg-Zr-Ni合金的非晶化和纳米晶化的过程.与非晶态Mg(Zr)Ni相比,纳米晶的Mg(Zr)Ni中氢更易放出,放电曲线主要呈现高电位放电特征,添加Zr后合金的放电容量有所下降.     

累积连续流变挤压对Al-Mg(-Mn-Fe)合金组织性能影响

目的 研究多道次累积连续流变挤压变形对Al-Mg(-Mn-Fe)合金组织演化和力学行为的影响,为高性能细晶Al-Mg(-Mn-Fe)合金的制备提供借鉴与参考。方法 采用连续流变挤压方法制备Al-Mg(-Mn-Fe)合金,对流变挤压态Al-Mg(-Mn-Fe)合金进行多道次累积连续流变挤压变形,研究多道次变形前后Al-Mg(-Mn-Fe)合金的微观组织和力学性能变化,讨论变形过程中Al6(Mn,Fe)相对动态再结晶的影响,揭示累积连续流变挤压态Al-Mg(-Mn-Fe)合金的强化机制。结果 经3道次累积连续流变挤压变形后,Al-Mg合金和Al-Mg-Mn-Fe合金的平均晶粒尺寸分别减小至21.5 μm和2.8 μm,细化效果显著;在多道次变形过程中,Al-Mg-Mn-Fe合金内的Al6(Mn,Fe)相逐渐破碎细化并趋于均匀分布,再结晶驱动力增加,阻碍再结晶晶粒长大;经3道次变形后,Al-Mg合金杆材的抗拉强度和伸长率同步提高至267.4 MPa和52.2%,而Al-Mg-Mn-Fe合金杆材的抗拉强度提高至364.2 MPa,伸长率降低至31.7%,该合金的强化机制主要包括细晶强化、位错强化和第二相强化。结论 累积连续流变挤压变形可有效细化合金内的晶粒及第二相,提高Al-Mg(-Mn-Fe)合金的综合力学性能。     

铝基非晶合金防腐蚀耐磨损性能的研究进展

Al基非晶合金具有优异的防腐蚀耐磨损性能.综述了Al基非晶合金由热处理和变形处理引起的晶化,介绍了Al基非晶合金材料防腐蚀耐磨损性能的研究现状,指出Al基非晶合金在控制非晶纳米晶比例、提高该非晶纳米晶涂层中非晶含量的研究动态,展望了Al基非晶合金材料在海洋装备防护等领域的运用价值.     

大塑性变形制备超细晶/纳米晶Al-Mg铝合金的研究进展

近年来,大塑性变形(SPD)制备具有先进结构和功能的超细晶和纳米晶Al-Mg铝合金的研究取得了很大进展。SPD后,合金的晶粒显著细化、位错密度提高及有非平衡晶界和晶界偏析形成,这些微观结构导致合金的强度、硬度大幅提高。然而,SPD合金的塑性普遍较低。综述了SPD制备的Al-Mg铝合金在结构和性能方面的一些最新研究成果。     

球磨CeMg12+100wt%Ni+Ywt%TiF3（Y=0、3、5）合金微观结构及电化学储氢性能

用球磨法制备具有非晶纳米晶结构的CeMg12+100wt%Ni+Ywt%TiF3(Y=0、3、5)电极合金,研究在球磨过程中加入不同含量的TiF3对合金的微观结构及电化学性能影响。主要从电化学放电容量、循环稳定性以及电化学动力学方面对制备的合金电化学性能进行探讨,并运用电化学PCT(压力–组成–温度)法从热力学角度进一步研究制备合金电化学性能变化的内在原因。结果表明:TiF3有助于增强球磨CeMg12+100wt%Ni+Ywt%TiF3(Y=0、3、5)储氢合金玻璃化形成能力,改善合金的电化学与动力学性能。另外,球磨过程中加入TiF3可以在一定程度上降低合金氢化物的热稳定性,有利于电化学释氢反应的进行。     

Ti—Fe二元系在机械合金化过程中的结构转变及纳米晶TiFe储氢合金的制备

研究了Ｔｉ－Ｆｅ和Ｔｉ－Ｆｅ－Ｍｎ纳米晶储氢合金的机械合金化制备，用Ｘ－ｒａｙ衍射分析了Ｔｉ－Ｆｅ和Ｔｉ－Ｆｅ－Ｍｎ在高能球磨的机械合金化过程中的结构变化及获得的ＦｅＴｉ相的晶粒尺寸。此外，还考察了球磨条件包括气氛、球磨机转速等对球磨过程中结构变化的影响。研究结果表明：采用适当的球磨参数并辅以后续热处理，可以制备出不同晶粒尺寸的纳米晶储氢合金，在本研究中获得的ＦｅＴｉ合金的最小平均晶粒尺寸可达１３ｎｍ。     

Al-Mg-Sc-Zr系富Al角相图评估

总结了近年来Al-Mg-Sc-Zr四元系相图的发展情况，分析了Al-Mg-Sc-Zr四元系中富铝角存在的中间相Al3Sc,Al3Zr,Al3(Sc1-xZrx),AlMgZr及它们的相结构，概述了添加Sc,Zr对Al-Mg合金的有益作用，指出了Al-Mg-Sc-Zr四元相图的价值和研究方向。     

Influence of annealing on the mechanical properties of compocast Al(Mg)-Al2O3 particulate composite

The annealing of cast Al(Mg)-Al₂O₃ particulate composite at temperatures of 673, 723 and 773 K for varying periods of time from 1–5 h resulted in reduction of strength and hardness similar to that occurring in cast Al-Mg alloy, due to homogenization. However, the ductility of the composite increased on annealing, contrary to that observed in cast Al-Mg alloy, presumably because the solution of the eutectic in the composite causes magnesium diffusion to the alumina particles resulting in further reaction to form magnesium aluminate and does not increase the magnesium level of its primary phase, as occurs in Al-Mg alloy.     

搅拌摩擦焊辅助Al/Zn/Mg接头扩散连接

对2mm厚的AZ31B镁合金和6061铝合金平板进行添加夹层Zn的搅拌摩擦诱导扩散连接实验。通过SEM,EPMA,XRD,拉伸实验和维氏硬度测试研究Al/Zn/Mg搭接接头显微组织和力学性能。结果表明:当旋转速率合适时,扩散层存在Al富集区,Al5Mg11Zn4层及Mg-Zn共晶区;而旋转速率较低时,扩散层存在残留的Zn层;旋转速率过大时,扩散层出现Al-Mg系金属间化合物。由于扩散层主要为金属间化合物,其显微硬度明显高于母材。Zn箔的加入提高了Al/Mg搭接接头的力学性能。断口观察分析表明,接头失效发生在靠近Al侧的扩散层上。     

不同Mo含量对Al-Mg合金轧板微观组织和短时高温力学性能的影响

基于高强度耐火Al-Mg合金开发需求,设计并制备了6种Mo含量(质量分数)的Al-Mg合金,经变形热处理获得H3xx态轧板,结合光学显微镜、X射线衍射仪、拉伸试验机、带有能谱仪(EDS)的蔡司扫描电镜(SEM)等表征设备对各合金轧板微观组织和短时高温力学性能进行检测分析,揭示了微量Mo对Al-Mg合金的强韧化机理。结果表明:Mo合金化H3xx态Al-Mg合金具有较高的力学性能,这主要归功于与铝基体呈半共格关系的Al₁₂Mo弥散相起到的弥散强化效果和抑制再结晶作用,但过量的Mo易使Al-Mg合金形成较高Mg固溶度的难熔Al₁₂Mo结晶相,不利于合金性能提升。Al₁₂Mo弥散相具有一定的高温稳定性,高温状态下显著阻碍再结晶晶粒长大,进而提高Al-Mg合金高温性能。Mo含量为0.08%时的高温性能最佳,高温强度最大提升22.5%。随着Mo含量的增加,Al-Mg合金常温力学性能和短时高温力学性能都有所提高。     

A novel method for the preparation of Al-Mg intermetallic coating

A novel method has been suggested to obtain an Al-Mg intermetallic compound coating on the ZL102 Al alloy by Al-Mg twin-wire arc spraying and gas tungsten arc melting (GTAM) post treatment. The composition and the morphology of the coating are characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) and the corrosion behavior is investigated by potentiodynamic electrochemical tests respectively. The results show that the components of the coating after GTAM are Mg₁₇Al₁₂, Al₃Mg₂ and Al. According to polarization curves and micro-hardness tests, the Al-Mg intermetallic coating exhibits good corrosion resistance and high micro-hardness.     

Tensile behavior of bulk nanostructured and ultrafine grained aluminum alloys

In the present study, data on tensile behavior of bulk nanostructured aluminum alloys processed via consolidation of mechanically milled powders and severe plastic deformation are analyzed. High strength and low strain hardening were observed in bulk nanostructured and ultrafine-grained Al alloys. The ductility of aluminum alloys decreases with decreasing grain size. The high amount of intercrystalline components may have an influence on tensile properties of bulk nanostructured materials when grain sizes are less than 100 nm. The high strength in bulk nanostructured Al-Mg alloy may be attributed to contributions arising from grain size strengthening, the presence of high dislocation densities, Orowan strengthening, precipitation hardening and solid-solution hardening. The large and sudden stress drops in the stress-strain curves of cryomilled Al alloys are most probably indicative of the dislocation annihilation in the vicinity of or breakaway from the strong pinning role of dispersoids.     

Influence of grain size on tensile properties of Al-Mg alloys

Abstract

Grain size refinement is an important strengthening mechanism in Al-Mg 5000 series alloys, which have a relatively large Hall-Petch slope compared with other Al alloys. In addition, the high work hardening rate exhibited by Al-Mg alloys provides excellent formability. This paper investigates the influence of grain size on the flow stress over a range of strains, and in several different Al-Mg alloys. It is found that the Hall-Petch slope decreases after yield, indicating that the large grain size effect is primarily associated with initiating plasticity in these alloys. Beyond yield the slope decreases to a value equivalent to other, non-Mg containing alloys, and shows no clear dependence on strain. The intercept stress from the Hall-Petch plots at different strains is non-linear with ? 1/2 for alloys containing up to 3 wt-%Mg, which indicates that the free slip distance is strain dependent in these alloys. In an Al-5 wt-%Mg alloy the intercept stress is linear with ? 1/2, indicating that solute atoms are controlling the free slip distance. If Mn is added to the Al-5 wt-%Mg alloy, as it is in commercial alloys, it has little influence on the grain size dependence, but it does increase the frictional stress at the highest Mn level of 0.7 wt-%.     

Evaluation of Al and Some of Its Alloys as Anode Materials vs γ-MnO2 as Cathode Material and Ore Produced γ-MnO2 vs Zn Anode in KOH Solution

In this study electrochemical performance of Al and some of its alloys (Al-Zn, Al-Mg and Al-Mn) anodes vs MnO2 cathode were carried out in alkaline solution. The results show that the Al-Zn alloy anode has the best cell capacity among the other alloys. Cell capacity values go in the order Al-Zn＞Al-Mg＞Al＞Al-Mn. This result is probably related to the nature of passive films formed on the surface of the alloys which examined by scanning electron microscopy (SEM). SEM morphologies of Al and its alloys showed coarse grains of passive films formed on the surface of these anode materials while Al-Mn morphology shows a needle-like structure.Electrolytic manganese dioxide (EMD) produced by electrodepositing on platinum anode from liquor resulting from reduction of low grade pyrolusite ore (β-MnO2) by sulfur slag was characterized as cathode in alkaline Zn-MnO2 batteries. Ore produced sample (EMD1) was performed well in comparison with EMD standard (EMD2) (commercial battery grade electrolytic manganese dioxide, TOSOH-Hellas GH-S). SEM morphology of Zn anode after cell reaction was carried out and showed that Zn anode has fine grains of passive film on its surface.