同步异步轧制对高压阳极铝箔织构的影响

简述同步和异步轧制工艺的特点,对比了不同轧制工艺对高压阳极铝箔冷变形及再结晶织构的影响.结果表明,同步、异步轧制铝箔退火后都可得到高的立方织构含量,但后者的压力小,生产成本低,采用异步轧制生产高压阳极铝箔,可以调整传统的高压阳极铝箔生产工艺,降低生产成本.     

异步轧制高纯铝箔在退火过程中织构的演变

采用异步轧制技术对高纯铝箔进行冷轧,利用加热和在冷水中淬火,把样品的高温态保存下来。通过ODF分析和反极图定量计算,对高纯铝箔微取向流变行为进行了研究。结果表明:立方织构{001}<100>是在再结晶退火过程中形成和发展的;适宜的速比,相应的形变量和与之相匹配的退火工艺,是获得强立方织构{001}<100>的前提。根据形变与再结晶理论,探讨了异步轧制高纯铝箔中立方织构{001}<100>的形成和发展。     

高纯铝箔在异步轧制和再结晶过程中取向的演变

采用不同速比的异步轧制技术对99.99%的高纯铝板进行不同形变量的冷轧,并对冷轧样品进行不同温度和时间的再结晶退火.利用X射线衍射技术和TEM观测探讨了异步轧制条件下高纯铝箔中变形织构和再结晶织构的演变.结果表明:高速比的异步轧制(i=1.28)在样品中产生相对较强的旋转立方织构{001}(110).异步轧制后退火的高纯铝箔样品中,立方{001}(100)织构组分的再结晶晶核的形成和长大存在一个临界转变温度,此温度与异步轧制的速比成反比.异步轧制有利于降低高纯铝箔的再结晶温度,这与异步轧制提高高纯铝箔的形变储能有关.异步轧制有利于在低温时形成强的立方{001}(100)织构组分,但此时漫散较大;随着退火温度的升高,漫散范围明显缩至8°-10°.     

电解电容器高压阳极用高纯铝箔再结晶组织研究

利用Axiovert 25型金相显微镜对高纯铝箔制备过程中的组织进行了观察和分析.结果表明,轧制变形量越大,高纯铝箔的再结晶组织越细小;高纯铝箔的再结晶过程经历了回复、再结晶和晶粒长大三个阶段;高纯铝箔开始再结晶温度在200℃～230℃之间.     

Formation mechanisms of recrystallization textures in aluminum sheets based on theories of oriented nucleation and oriented growth

The recrystallization textures in 95% rolled aluminum sheets with different purities and initial textures were investigated. The effects of recovery levels and the dragging effects induced by impurities on the effective driving force and corresponding behaviors of oriented nucleation and oriented growth during annealing were analyzed. The oriented nucleation is a common behavior in the initial stage of primary recrystallization if the effective driving force in deformed matrix is not too high to reduce the necessity of nucleation period. Oriented growth might appear if the temperature is not too high and the grains, of which the misorientation to matrix is about 40°〈111〉, have enough time and space to expand growth advantages, while certain reduction of effective driving force is also necessary. The recrystallization textures could be changed by controlling initial textures and effective driving forces which can be regulated by recovery levels and dragging effects.     

Microstructure and texture development of pure aluminum and aluminum alloy processed by high speed hot rolling

The microstructure and texture development of pure aluminum and aluminum alloy processed by high speed hot rolling are investigated. The aluminum sheets are rolled at temperatures ranging from 410°C to 560°C at a rolling speed of 15m/s without lubrication and quenched into water at an interval of 30 ms after rolling. The redundant shear strain induced by high friction increases beneath the surface at a reduction above 50% for Al alloy (AA5052) and above 60% for pure Al (AA1050). Dynamic recrystallization occurs in the surface region when the equivalent strain exceeds a critical value that depends on rolling temperature, while only recovery occurs in the center region. The critical equivalent strain for the occurrence of recrystallization in AA5052 is lower than that in AA1050. When the large strain is introduced beneath the surface, the shear texture, the main components of which are {001}<110> and {111}<110>, develops. In the center region, Cu-orientation and cube orientation develop. The shear texture beneath the surface is weak when recrystallization occurs.     

冷轧低压电子铝箔退火加热过程中的再结晶和晶粒长大

采用EBSD微取向分析、织构定量分析、晶粒尺寸分析等手段研究了低压电子铝箔不同退火加热过程对再结晶和晶粒长大行为的影响,并利用再结晶理论对相关过程进行了讨论.初次再结晶前的回复处理会明显降低冷轧铝箔的储存能及再结晶驱动力,并对再结晶晶粒尺寸和立方织构量产生规律性影响.特定的退火加热过程会诱发电子铝箔的晶粒异常长大,并导致立方织构量的明显下降.     

Cube orientation in hot rolled high purity aluminum plate

X-ray diffraction and orientation mapping in EBSD measurement were applied to obtain information of deformation and recrystallization with the emphasis on the cube orientation in hot rolled high purity aluminum plates.It is shown that cube orientations are retained to a large extent during hot rolling.Some deformed cube grains are found to have experienced large extent of recovery according to their Kikuchi band contrasts.The deformed cube-oriented grains in hot rolled plates are in an unfavorite growth condition with respect to their neighboring grain orientations for the subsequent annealing.The reasons for the phenomena observed,as well as the influence of hot rolling process on subsequent cold rolling and final annealing were discussed.     

形变量对6111铝合金再结晶织构的影响

采用取向分布函数(ODF)法研究了冷轧形变量对6111铝合金再结晶织构的影响。结果表明:6111铝合金的再结晶织构主要由Cube ND15和{011}<111>织构组分构成;随冷轧形变量的增加,这两种织构组分的取向密度逐渐升高,但二者升高的速度并不相同,{011}<111>组分取向密度升高的速度比Cube ND15组分的快,当冷轧形变量大约为50%时,{011}<111>组分的取向密度超过Cube ND15组分的。     

Evolution of the bulk microstructure in 1100 aluminum builds fabricated by ultrasonic metal welding

The annealed 1100 aluminum foils were welded at room temperature with an ultrasonic metal welding (UMW) method. Effects of two key parameters (the oscillation amplitude and the deformation reduction of the welded foils) on the microstructural evolution were investigated. With the increase of oscillation amplitude, the deformation and the grain refinement of the foils in the welded specimen were homogeneous, but the grain size was not less than 25 μm. With the increase of deformation reduction, the microstructures were inhomogenously changed from the initial coarse grains (45 μm) into the dynamically recrystallized fine grains (2 μm) in the upper foil, but they changed little in the lower foil. For both cases, the microstructural evolutions attributed to the grains and/or sub-grains rotation. The dynamic recovery and the followed continuous dynamic recrystallization were the active deformation mechanism during UMW according to the observation of the thermal and the deformation textures. The effects of both ultrasonic amplitude and deformation reduction on the hardness of the builds were measured.     

超高强DP980钢的动态再结晶模型

采用Gleeble-3500热模拟试验机对超高强DP980钢进行热压缩试验,研究其在变形温度为900~1 200℃、应变速率为0.05~30s~(-1)条件下的动态再结晶行为,分析了变形温度和应变速率对真应力-真应变曲线的影响。结果表明:超高强DP980钢在变形过程中,存在动态再结晶和动态回复两种软化机制,且随着温度的升高和应变速率的降低,临界应变越小,动态再结晶越容易发生;同时,得到了发生动态再结晶时的形变激活能,建立了峰值应变模型、动态再结晶临界应力模型和动态再结晶动力学模型。     

铝合金LF6变形工艺与微观组织关系的研究

研究了防锈铝合金LF6热变形工艺对组织的影响.实验表明：随变形程度的增大,组织呈带状分布现象变得明显：在热加工过程中,试样组织发生了动态回复或动态再结晶;随温度的升高,出现晶粒长大的现象.     

铝合金LF6变形工艺与微观组织关系的研究

研究了防锈铝合金LF6热变形工艺对组织的影响。实验表明:随变形程度的增大,组织呈带状分布现象变得明显;在热加工过程中,试样组织发生了动态回复或动态再结晶;随温度的升高,出现晶粒长大的现象。     

Effect of Laser Texturing on the Microstructure and Textures of 1050 Aluminum Alloy

To improve the surface morphology, formability, and deep drawing properties of 1050 aluminum alloy sheets, laser-textured rolls were used in cold rolling process. Effects of laser-textured rolls, comparing with conventional ones, on microstructure and texture of aluminum alloys after rolling and following recrystallization were studied. In aluminum sheets processed by laser-textured rolls and conventional rolls, microstructure and texture were similar after rolling, but significantly different after recrystallization. Laser texturing process results in finer and inhomogeneous recrystallized grains. The recrystallization texture of the specimen rolled with conventional roll has a major cube component and a minor R component. The intensity of cube component increases with increasing annealing temperature. However, recrystallization texture of the specimen rolled with laser-textured roller is much more random. The specimen shows that recrystallization texture has only a weak cube orientation but strong rotated-cube orientation as well as a much higher fraction of random orientation.     

GH4169合金楔横轧微观组织演变及动态再结晶机制

采用金相显微镜和电子背散射衍射(EBSD)技术分析了楔横轧制备的GH4169合金轧件的微观组织演变和动态再结晶机制;利用数值分析方法获得了楔横轧过程中等效应变、应变速率和温度的相互关系和变化规律,并探讨对楔横轧GH4169合金动态再结晶的影响。结果表明,楔横轧的变形特点是导致GH4169合金组织均匀和动态再结晶机制不同的主要原因,较大的断面收缩率有利于组织均匀化;轧件表面以非连续动态再结晶机制为主,而心部以连续动态再结晶机制为主。     

PRIMARY RECRYSTALLIZATION TEXTURES OF 70-30 BRASS ROLLED BY CROSS SHEAR ROLLING IN SINGLE DIRECTION

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Flow stress modeling and warm rolling simulation behavior of two Ti–Nb interstitial-free steels in the ferrite region

Axisymmetric compression tests and compact strip production (CSP) warm rolling simulations were carried out on two commercial Ti–Nb stabilized interstitial-free (IF) steels to investigate their flow behavior in the ferrite region. The comparison between the measured and predicted stress curves indicated that dynamic recovery was the dominant softening mechanism during axisymmetric compression deformation. The flow stress curves during CSP-warm rolling simulations indicated that static and dynamic recovery dominated the softening process for early passes and an apparent dynamic recrystallization contributed to the flow stress reductions for the last two passes. The microstructural evolution during the simulation confirmed that the very fine quasi-equiaxed ferrite grains obtained could be explained by apparent dynamic recrystallization, which was assisted by dynamic recovery at high temperature and a reduced Nb solute drag.     

应变速率和固溶处理对7075铝合金锻件动态再结晶的影响

通过对不同状态的7075铝合金以不同的应变速率和不同的应变锻造，并利用了光镜(OM)、透射电镜(TEM)对热变形显微组织进行观察。实验表明：对于7075铝合金，较高的应变速率有利于出现动态再结晶，动态再结晶的方式为不连续动态再结晶，当应变速率较低时，只出现动态回复。弥散的第二相粒予在动态再结晶过程中起了重要作用。     

中间退火前后冷轧变形量对3003铝合金阴极箔比电容的影响

采用扫描电镜及能谱仪,透射电镜和比电容检测等方法研究了中间退火前后冷轧变形量对3003铝合金阴极箔第二相分布及比电容的影响.结果表明:随着最终冷变形程度的增加,位错密度增大,从而比电容值显著提高;最终冷轧变形量为90%时,比电容达到最大值,继续增加冷轧变形量,比电容值反而下降;但对于最终冷轧变形量95%的箔材,由于中间退火前冷轧变形量较低,使得退火过程中析出的弥散第二相数目减少,最终导致成品箔中的腐蚀位置减少,比电容降低.     

应变速率对7050铝合金塑性成形性能与动态再结晶的影响

利用刚粘塑性有限元与动态再结晶演化热力耦合的方法,进行了7050铝合金热压缩过程变形与动态再结晶的热力耦合模拟,讨论了应变速率对7050铝合金塑性成形与动态再结晶的影响.模拟结果表明,热变形过程中,试样的各个部位的变形分布不均匀,心部的等效应变最大,变形的不均匀性随应变速率的增大而增大,但是变化的程度不大;试样内部各部位的应力大小分布不均匀,随应变速率的增大,最小应力值由自由变形的鼓形区域逐步向心部移动;动态再结晶品粒尺寸标准偏差随应变速率的增加而减小.