DC AA 5052铝合金冷轧板沿厚度方向织构变化的X射线衍射分析

以不同变形量对预先经过热轧和再结晶退火的DC AA 5052直接冷却铸造铝合金板进行冷轧制后,采用X射线衍射和专用软件测试、计算并分析表层、1/4厚度层、中心层的织构极图和ODF图及有关数据,研究板厚度方向轧制织构的变化情况,以为改进轧制工艺、获得板厚度方向的织构织及性能均匀性提供依据。各变形量的试样之表层向1/4层、中心层方向,存在β织构逐渐增强的梯度;变形量逐渐增大到90%的过程中,沿板厚度方向β织构强度的变化梯度逐渐降低、体积分数逐步增大、强度逐渐增大并达到各层基本接近。     

冷轧CC5052铝合金板表层至中心层织构变化的X射线衍射分析

为了对铝合金板轧制技术发展提供依据,采用X射线衍射仪测试极图并使用专用软件计算织构的ODF,研究了热轧后经过454℃×4h预先再结晶退火处理的5052双履带连续冷却铸造铝合金板,进行不同变形量冷轧后自表层至心部层的织构分布状况。冷轧制后变形量小于40%的试样,存在织构强度由表层向中心层提高的变化梯度。变形量大于56.1%的试样,β织构的增加主要是来自剩余位向转变量随变形量的增加;主要织构β较强、Goss和剩余位向较弱,各层之间的织构状态接近。     

CC5083与CC5182铝合金冷轧与再结晶后偏光金相观察组织和X射线检测织构对比研究

连续冷却铸造5083铝合金板较大塑性变形量冷轧后的组织、织构及性能与再结晶处理工艺关系的研究有限。对冷轧压下量约为91.5%的CC5083与CC5182铝合金板分别进行室温入箱式电炉、随炉不限速升温到不同温度退火2 h和分别进行直接入不同温度盐炉退火30 min、出炉水冷至室温后,采用偏光金相显微镜观察组织、采用X射线衍射检测织构,进一步对比研究较大压下量冷轧后退火工艺与再结晶组织和织构关系。结果显示：(1)电炉退火CC5083铝合金板的再结晶开始及晶粒长大温度为343 ℃,晶粒长大后形状为长条状(创新点);盐炉退火CC5083铝合金板的再结晶开始温度为343 ℃;二者再结晶完成温度都为371 ℃。(2)CC5182铝合金板分别在电炉与盐炉454 ℃以上退火,晶粒开始显著长大;电炉退火与盐炉退火CC5083铝合金板再结晶开始温度分别高于电炉与盐炉退火的CC5182铝合金板,盐炉退火CC5083铝合金板再结晶晶粒长大温度高于另外三种方式退火;CC5182铝合金板盐炉退火再结晶晶粒长大温度高于电炉退火的。CC5083和CC5182铝合金冷轧板表层再结晶及再结晶晶粒长大温度明显高于内层的(创新点)。(3)四种方式退火再结晶晶粒长大温度及相同温度退火时织构转变程度有差异(创新点);退火过程中织构检测结果与金相组织观察结果反映的再结晶进程不很一致。     

银基带再结晶织构的EBSD分析

本文采用EBSD(电子背散射衍射)等分析手段对{110}<110>取向的银基带的织构形成机理进行了深入研究,发现了冷轧织构与不同退火温度下再结晶织构间的取向转变关系,研究发现,{110}面附近且非{110}<211>取向的冷轧织构组分,900℃退火可以转变为强的{110}<110>织构.织构转变中有孪晶形成,{110}<110>和{110}<114>取向互为孪晶关系.     

高温超导Ni-W基带的织构研究

涂层超导是目前国际超导界的研究热点和重点,所采用的韧性金属基带多为Ni和Ni-W合金.本文采用粉末冶金方法制备了Ni-3 at.%W和Ni-5 at.%W合金.利用轧制辅助双轴织构基带(RABiTS)技术制备了Ni-W合金基带,系统研究了Ni-W合金形变和再结晶织构转变规律.研究表明:通过大变形量的冷轧和高温再结晶退火,可以得到强立方织构的Ni-W合金基带.     

两相钛合金再结晶退火组织与织构演变的蒙特卡罗模拟

蒙特卡罗(MC)方法被广泛应用于模拟金属材料在退火过程中的静态再结晶行为. 在已有两相材料晶粒长大MC模型基础上, 引入形核阶段, 综合考虑再结晶晶粒吞并形变晶粒和再结晶晶粒竞争长大两种情况, 建立了退火时两相合金再结晶MC模型.结合电子背散射衍射所测 初始晶粒形貌、相成分、晶体学取向及应变储能相对值, 该模型被应用于TC11钛合金退火过程中的微观组织及织构演变模拟.结果表明, 所建模型能够较好体现退火过程中两相晶粒的形核及晶粒长大行为. 与β相相比较, α相具有较低的再结晶速率和较高的晶粒长大速率, 前者主要归结于α相较低的初始应变储能, 后者则体现了该条件下初始组织形貌、分布及两相比例对晶粒长大具有重要影响; 由于非均匀形核的影响, 模拟得到的再结晶速率变化与 假设均匀形核的Johnson-Mehl-Avrami-Kolmogorov 再结晶方程存在明显差异.同时, 两相的基本织构特征在退火过程中无明显变化, 但织构强度增加. 关键词： 两相钛合金 再结晶 蒙特卡罗方法 织构     

普通铸造和低频电磁铸造7050铝合金电阻率-温度特性的研究

利用四端接线法测量以普通铸造(DC)和低频电磁铸造(LFEC)两种不同方法制备的7050铝合金的电阻率-温度曲线. 发现升温曲线在250℃有一斜率转变点,且LFEC样品电阻率随温度变化得要快;由室温至900℃的过程中,LFEC试样的液固相线温度均高于DC试样;而DC试样在900℃保温甚至降温至600℃电阻率都显著增大. 结合金相显微组织的观察,对上述现象进行理论分析. 关键词： 低频电磁铸造 电阻率 铝合金 洛伦兹力     

强磁与应力场耦合作用下AZ31镁合金塑性变形行为

研究强磁场对AZ31镁合金塑变能力和微观组织的作用,在3 T脉冲强磁场条件下对合金进行磁场耦合应力时的拉伸实验.采用电子背散射衍射、Ⅹ射线衍射和透射电镜分析等方法研究材料的微观组织.结果表明:与0 T拉伸试样相比,3 T拉伸试样抗拉强度和延伸率分别提高了2.2%和28.7%,说明将强磁场耦合作用于材料塑性变形过程时,能在不降低材料强度的同时提高镁合金的塑性变形能力,有助于同步改善材料强韧性.磁场作用机理主要表现为磁致塑性效应,计算表明主要合金相β(Mg_(17)Al_(12))为顺磁性,有助于发挥磁场作用效果.磁场提高了位错运动灵活性并促使位错增殖,晶界处位错堆积和应力集中促进了再结晶形成,晶粒发生细化,发挥细晶强韧化效果;同时磁场诱发塑性变形时的晶粒转动,新生成非基面取向的晶粒弱化了镁合金(0001)基面织构,该组织特征有助于提高材料的塑变能力.     

双掺杂BaxAgyCa3-x-yCo4O9氧化物的织构与电输运性能

采用柠檬酸溶胶凝胶和放电等离子烧结制备了Ca位双掺杂型的BaxAgyCa3-x-yCo4O9烧结体,利用X射线衍射仪、扫描电子显微镜、电阻率测试仪等研究了烧结体相组成、取向度、织构及电性能.结果表明:含Ag的掺杂试样中出现了偏离化学计量比分布的Ag单质,掺杂试样取向度随Ba与Ag掺杂量之比x/y的增大而提高,含Ag的掺杂试样取向度低于未掺杂试样,不含Ag的掺杂试样取向度高于未掺杂试样.x=y=0.1的试样导电机理发生变化.Ba,Ag掺杂量相等的试样保持较低取向度的同时具有较低的电阻率,在973 K时达到最低值(7.3 mΩcm),而取向度最低的Ag单掺杂试样电阻率在所有试样中最低,在973 K时为6.3 mΩcm.     

PyC的广义小滴沉积模式

通过偏光显微镜、扫描电镜(SEM)、X射线衍射(XDS)及X射线光电子能谱(XPS)考察了热解碳(Pyrocarbon,本文简写为PyC)的织构及生长特征等,提出了一个广义小滴沉积模式.PyC的光滑层(SL)、粗糙层(RL)及各向同性相(ISO)等三种主要织构的形成机制可由此模式得到满意的解释.     

Effect of initial texture on texture evolution in cold-rolled AA 5182 aluminium alloy

AA 5182 aluminium alloy with a strong cube texture was cold rolled to different reductions along the following directions: firstly, the original rolling direction; secondly, at angles of 22.5 and 45° to the original rolling direction. The evolution of texture in the cold-rolled samples with different initial textures was then investigated by X-ray diffraction. The texture evolution was quantified by mathematical formulae of texture volume fractions and rolling true strain. The results show that initial texture has a strong influence on the evolution of rolling texture. AA 5182 aluminium alloy with an initial rotated-cube (r-cube) (45° normal direction r-cube) texture exhibits the fastest rate of formation of the β fibre. The rate of formation of the β fibre decreases as the initial texture changes from the r-cube texture to the cube texture. The relationship between the rate of formation of the β fibre (k _β value in the mathematical formula for the volume fraction of the β fibre) and the initial texture (M _cube and M _r-cube: the volume fractions of the cube and r-cube components respectively) can be expressed as k _β ?=?0.37???0.03(M _cube /5.41???M _r???cube /5.64).     

基于微束X射线荧光的铸轧7B05铝合金元素偏析研究

材料内部微观尺度上成分、组织结构控制精度低、波动大是制约高铁铝合金国产化进程的重要原因,因此从微观尺度上研究大尺寸铝合金成分均匀性至关重要。鉴于目前研究铝合金偏析的区域通常较小且不连续,定量统计方法过于简单。使用微区分辨率较高的微束X荧光与原位定量统计分布分析技术相结合的方法,从点、线、面、频度分布等方面对成分分布数据进行解析,研究了较大尺寸范围内铝合金成分偏析的规律。研究结果表明铸轧7B05铝合金截面中心层存在接近2 mm的偏析带,Al,Cr,Ti和Zr元素为正偏析元素,中心层含量比上下表面高,Cu,Fe和Zn元素为负偏析元素,中心层含量比上下层含量低;各元素含量分布的统计偏析程度整体较小,分布最均匀的为Al元素,统计偏析度最小为0.01%,Ti和Fe元素分布较不均匀,统计偏析度分别为0.81%和0.6%;Fe元素与Mn元素在面分布中出现较明显的点状偏析,这是由于铝合金铸造过程中经显微偏析形成的金属间化合物,在后续的热轧成型中破裂成多个连续排列的第二相所致。使用激光诱导击穿光谱法对该方法所得数据进行验证,结果显示在30 mm×6 mm尺寸范围内所测元素面分布与线分布结果与荧光结果趋势完全一致。综上所述,使用微束X荧光结合原位统计的方法,对铸轧7B05铝合金点、线、面、频度分布及偏析程度的计算,可提供大量分析数据,对于量化研究大尺寸范围内轧板截面组织、性能的波动趋势具有重要意义。     

Features of Forming a Structure of the Copper-Zinc Alloy Coating on the Aluminum Alloy Surface by Friction Stir Processing

Russian Physics Journal - The structure of samples of the C27400 copper alloy coatings on the AA5056 aluminum alloy surface, produced by friction stir processing of a rolled sheet package is...     

Evolution of texture and grain boundary microstructure in two-phase (α + β) brass during recrystallization

The evolution of texture and microstructure during recrystallization is studied for two-phase copper alloy (Cu–40Zn) with a variation of the initial texture and microstructure (hot rolled and solution treated) as well as the mode of rolling (deformation path: uni-directional rolling and cross rolling). The results of bulk texture have been supported by micro-texture and microstructure studies carried out using electron back scatter diffraction (EBSD). The initial microstructural condition as well as the mode of rolling has been found to alter the recrystallization texture and microstructure. The uni-directionally rolled samples showed a strong Goss and BR {236}?385? component while a weaker texture similar to that of rolling evolved for the cross-rolled samples in the α phase on recrystallization. The recrystallization texture of the β phase was similar to that of the rolling texture with discontinuous ?101? α and {111} γ fiber with high intensity at {111}?101?. For a given microstructure, the cross-rolled samples showed a higher fraction of coincident site lattice Σ3 twin boundaries in the α phase. The higher fraction of Σ3 boundaries is explained on the basis of the higher propensity of growth accidents during annealing of the cross-rolled samples. The present investigation demonstrates that change in strain path, as introduced during cross-rolling, could be a viable tool for grain boundary engineering of low SFE fcc materials.     

晶粒取向镍—铁合金各向异性的磁转矩法研究

本文测定了冷轧的及冷轧后又经不同温度退火的50％Ni-50％Fe合金的磁转矩曲线,从而对试样中的冷轧及再结晶结构作了推断。从具有完整立方结构的试样上测得的磁晶各向异性常数k₁和其他作者从单晶体上得到的值相近,而从保有冷轧结构的试样定得的k₁值则较大。考察了影响k₁测定值的可能因素;讨论了磁致伸缩各向异性导致的弹性能以及有序程度对k₁值的影响。 关键词：     

Recent developments in semiprocessed cold rolled magnetic lamination steel

Over the past 10 years the magnetic property performance of semi-processed cold rolled magnetic lamination steels in North America have approached those of nonoriented, semi-processed silicon steel. This improvement was accomplished via higher alloy levels in conjunction with hot band annealing. New temper rolling strategies can produce weakly oriented steels tailored to specific applications, such as small transformers used in fluorescent lighting ballasts. Recently, production trials for 0.0138 in product cold rolled on tin mills has been undertaken. Efforts to further improve properties through a better understanding of texture control and via implementation of new production processes, such as thin slab or strip casting, continue.     

Influence of thermomechanical processing on shear bands formation and magnetic properties of a 3% Si non-oriented electrical steel

The effect of thermomechanical processing on the formation of shear bands and on the magnetic properties of a 3.0 wt% silicon non-oriented steel was investigated by hot rolling samples with different thicknesses at different temperatures, in order to obtain a variation in hot band grain size and cold strain. All the samples were processed in a single-stage cold rolling and finally annealed at 1020 °C. It was found that the increase of the hot band grain size decreases the γ fiber volume fraction and increases the η fiber volume fraction after the final annealing. The increase of the cold strain strongly contributed to this result. A good combination of intense generation of shear bands, and proper crystallographic texture, due to higher nucleation of grains with favorable orientations to magnetization in these bands, can be obtained for the samples hot rolled at 1000 and 1120 °C and submitted to cold strain of 64.3% and 72.2% respectively. However the best combination of B₅₀, W_15/60 and μ_r can be obtained by hot rolling the samples at 1000 °C to the thickness of 1.4 mm, corresponding to 64.3% of cold strain.     

Annealing texture of a cold-rolled Fe–Mn–Al–Si–C alloy

The study of recrystallization texture of a cold deformed Fe–Mn–Al–Si–C alloy, with about 30% Mn, has been discussed in this paper. The alloy is fully austenitic at room temperature, and therefore, principal FCC rolling textures were developed in this material at different stages of cold rolling. The present study was undertaken to observe the transformation of FCC rolling texture during recrystallization of a heavily cold deformed specimen. It was observed that isothermal annealing at 750 °C led to a weak recrystallisation texture, which was quite similar to the deformation texture developed at the early stage of cold rolling. During recovery stage, a strong Bs/Goss-type texture was developed, which was identified as a new observation in this work.