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。     

DC与CC 5052铝合金冷轧后沿厚度方向织构分布状态对比的X射线衍射分析

采用X射线衍射测试极图、使用专用软件计算织构取向分布函数(ODF), 研究了热轧后454℃×4h再结晶退火的直接铸造5052铝合金板(DC 5052)和双履带连续冷却铸造5052铝合金板(CC 5052)冷轧制到不同压下量的试样,自表层至心部层的冷轧织构分布差别,为工业上生产及应用DC 5052与CC 5052铝合金冷轧板提供依据。结果显示：同样的大压下量时CC 5052的β织构强度及体积分数高于DC 5052的。冷轧前CC 5052的再结晶织构Cube的体积分数小于DC 5052的,剩余位向的体积分数多于DC 5052的,导致CC 5052表层的β织构强度及体积分数达到与1/4层、中心层接近所需要的冷轧压下量比DC 5052试样需要的小。CC 5052冷轧板冲压加工方面的性能优于DC 5052冷轧板。     

用于YBCO高温超导涂层的立方织构铜基带制备

Cu是制备双轴织构YBCO高温超导涂层的优良基带材料之一,立方织构的铜带可以提供良好的外延生长环境。文中采用轧制辅助双轴织构基带技术(RABiTS),研究了立方织构铜基带的制备工艺。将铜锭在初轧变形量达到88.4%后,进行400℃退火30min,再经二次轧制总变形量达到99.07%后,在氩气环境125—850℃之间不同温度下退火30min。用March-Dollase函数计算该系列样品的r值,其中850℃退火的样品具有最强的200择优取向,r值为0.25,用不完整极图对该样品的织构情况做进一步分析,用ODF函数定量计算了该样品立方织构的体积百分含量。该样品形成了较强的{001}<100>立方织构,体积百分含量为70.8%。     

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.     

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。     

分段PELE弹体冲击多层靶板数值分析

为了实现侵彻体对多层靶板的高效毁伤,采用数值模拟方法研究了分段式横向效应增强体(PELE)对4层金属靶的侵彻效应,获得了弹体侵彻速度和靶板厚度对弹体终点效应的影响。结果表明,分段PELE弹侵彻4层靶的靶后效果优于普通PELE弹。与金属杆相比,分段PELE弹侵彻多层靶后的弹孔直径更大。弹丸贯穿各层靶板后壳体的径向速度峰值随着靶板厚度的增加而增大,而壳体破碎长度并不随之线性变化。提高弹丸侵彻速度时,弹丸穿过第1层靶板后壳体破碎长度的变化趋势与径向速度峰值的变化相似,穿过第2层和第3层靶板后壳体破碎长度和径向速度峰值在侵彻速度为1.4km/s时达到极大值,随后下降,而穿过第4层靶板后壳体破碎长度和径向速度峰值随着初速度的增加而增大。     

冷却倾斜板熔体处理过程边界层分布及流动传热的理论研究

针对倾斜板熔体处理晶粒细化与半固态成形原理,研究了倾斜板熔体处理过程边界层分布,建立了熔体传热和冷却速率的计算模型.计算结果表明,随着斜板倾角和熔体初始流动速度的增大,熔体在倾斜板上从层流向紊流的转变时间减少;温度边界层厚度随着熔体初始流动速度的增加而减小,斜板倾角对温度边界层厚度的影响较小;温度边界层厚度和速度边界层厚度都随熔体流动距离的增加而增大,在层流区,温度边界层厚度远大于速度边界层厚度,而在紊流区,温度边界层厚度与速度边界层厚度重合;倾斜板上熔体冷却速率与熔体厚度成反比,初始流速小于1m/s时,熔体的冷却速率沿着倾斜板长度方向逐渐增大,初始流速为1m/s时,熔体的冷却速率沿倾斜板长度方向基本不变,当初始流速大于1m/s时,熔体冷却速率沿倾斜板长度方向逐渐减小;倾斜板上熔体冷却速率在100—1000 K/s之间,属于亚快速凝固范畴.     

基于逆向空间偏移拉曼光谱技术的多层混浊样品深层分析研究

空间偏移拉曼光谱（SORS）能够准确、快速、无损检测多层混浊介质样品深层生化构成信息。该研究通过搭建集成化逆向SORS光谱分析装置,在实现逆向SORS和背散射式拉曼光谱两种不同的光谱检测模式的基础上,检测与分析了不同空间偏移量（Δs）条件下双/三层组织模型内的深层拉曼光谱信息,并根据几何光学理论和投影测量原理,量化标定了Δs与锥透镜空间位置之间的关系,这为精确控制光谱检测条件提供了保障。为了验证该装置的检测能力,采用由羊肩胛骨/对乙酰氨基酚组成的双层模型和猪皮/硅橡胶/对乙酰氨基酚组成的三层模型,获得不同Δs条件下包含样品表层和深层信息的混合光谱。并进一步对该混合光谱进行面积归一化处理,观察到随着Δs的增大样品表层的拉曼贡献逐渐减小,而第二层以及第三层的拉曼贡献逐渐增大的现象。在此基础上,通过选择模型中每层物质的拉曼特征峰计算其相对拉曼强度,分析研究了相对拉曼强度、空间偏移量与样品厚度三者之间关系,即当Δs增大时相对拉曼强度比值随之增加,这清晰地表明深层物质的拉曼强度增加。然而,在同一Δs条件下,相对拉曼强度随着表层物质厚度的增大而减小。以上实验结果表明,我们搭建的集成化逆向SORS光谱分析装置可从深度达8 mm的生物模型下获取光谱信息,并证明了该装置在经皮无损探测方面的应用价值。     

Bi-2223/Ag多芯超导薄带的制备及其性能研究

采用PIT法制备银包套Bi-2223多芯超导薄带,研究了不同厚度带材的制备工艺和性能特点.采用不同的轧制变形量,将Bi-2223/Ag多芯线轧制为0.4mm～0.07mm不同厚度的带材.试验结果表明,厚度越薄的带材热处理温度较低,相变速度更快.由于组织均匀性和超导相的相对含量及织构的影响,不同厚度带材的临界电流密度有很大差异,厚度为0.1mm左右带材的临界电流密度最高,用这样的薄带可以绕制内径更小的线圈.     

离子束溅射Ge量子点的应变调制生长

采用离子束溅射技术制备了单层和双层Ge量子点, 通过原子力显微镜对比了不同Si隔离层厚度和不同掩埋量子点密度情况下表层量子点的尺寸和形貌差异, 系统研究了掩埋Ge量子点产生的应变对表层量子点的浸润层及形核的影响, 并用埋置应变模型对其进行解释. 实验结果表明, 覆盖Ge量子点的Si隔离层中分布着的应变场, 导致表层量子点浸润层厚度的降低, 从而增大点的体积; 应变强度随隔离层厚度的减小而增加, 造成表层量子点形状和尺寸的变化; 此外, 应变还调控了表层量子点的空间分布. 关键词： Ge量子点 埋层应变 离子束溅射     

Effect of initial orientation on the tensile properties of commercially pure titanium

Effect of crystallographic texture on uniaxial tensile deformation of commercially pure titanium was studied using in situ as well as post-mortem electron backscatter diffraction and elastoplastic self-consistent simulations. Correlation of mechanical properties and strain hardening response with deformation micromechanisms like different modes of slip and twinning was established. Tensile specimens were machined along rolling direction in the plane perpendicular to normal and transverse direction (sample A and C, respectively) as well as along transverse direction in the plane normal to rolling direction (sample B) to obtain different initial texture from cold rolled and annealed plate of commercially pure titanium. Sample B showed higher strength but lower strain hardening rate and ductility than the orientations A and C. It showed extension twinning with lateral thickening while the other samples showed coexistence of extension and contraction twinning. Schmid factor accounted for most of the observed twinning although some contraction twinning in sample A is attributed to the effect of internal stresses. A combination of in situ tensile test in a field emission gun scanning electron microscope with electron backscatter diffraction facility and elastoplastic self-consistent simulations aid in obtaining high-fidelity Voce hardening parameters for different slip and twinning systems in commercially pure titanium. The variation in tensile properties can be explained on the basis of propensity of twinning which tends to provide strain hardening at lower strain but contributes to failure at higher strain.     

Melting behavior of the oriented β-phase polypropylene texture crystallized by the temperature slope method

Isotactic polypropylene consisting of uniaxially oriented P-phase lamellae was crystallized in a temperature gradient. The β → α transition was investigated by simultaneous measurements with differential scanning calorimetry (DSC) and X-ray diffraction using synchrotron radiation (SR). To compare the transition mechanism, the β-phase sample was deformed by rolling it along the direction of the crystallization. During rolling, the β-crystal is deformed by interlamellar and interchain slip, which induces c-axis-oriented molecules along the rolling direction. The melting behavior is changed by the rolling deformation. For the as-grown β-crystal, the DSC thermogram has three peaks: the β-melting endotherm at 150°C, an exotherm by recrystallization into the °-form, and the endotherm at 167°C caused by melting of the recrystallized α-form. After the rolling deformation, the β-endotherm is extinguished by the successive exotherm. Simultaneous X-ray measurements reveal that the β → α transition is shifted to a lower temperature and that the recrystallized α-form has a c-axis-orientation caused by the rolling deformation. In the process of the β→ α transition, higher-order lamellar structure is developed earlier than formation of the crystalline structure. In this study, the heating phenomena, such as the β α transition and thickening of the β- and α-lamellae, are consistently explained by a mechanism involving melting and subsequent recrystallization.     

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).     

Application of SSNTDs for study of boron distribution in alloys

A study of boron behavior and its distribution in boron doped iron-, nickel- and aluminum-base alloys subjected to various treatment conditions has been performed. For this purpose a technique based on the detection of ¹⁰B(n,)⁷Li reaction products with track etch detectors has been applied. High boron enrichment of grain boundaries of both iron base and ingot nickel base alloys has been observed. After hot and then cold rolling of the latter specimens boron rearrangement along with the proper deformation of the structure took place. Striation of boron in a hot rolled aluminum alloy along the rolling direction has been observed.     

Influence of cold rolling on the anisotropy of the shear modulus and the poisson coefficient of polycrystalline copper and silicon steel

We consider a method for calculating the anisotropy of the shear modulus and the Poisson coefficient in the rolling plane for textured polycrystalline materials with a cubic lattice, which makes use of the integrated texture characteristics for averaging over the single-crystal properties, which are a certain combination of direction cosines in the sample coordinates, averaged with respect to orientation. The integrated texture characteristics are determined from two experimentally opposite polar figures of the plates. We study the influence of the amount of deformation during cold rolling on the anisotropy of the plate properties listed above for copper and silicon steel. The accuracy in the calculations is better than 5%. The results are compared with data from other authors. K. D. Ushinskii Institute, Odessa. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 25–29, February, 1993.     

Texture development during cold rolling of Fe–Cr–Ni alloy-experiments and simulations

Abstract

In the present work, evolution of microstructure and crystallographic texture during cold rolling of two phase Fe–Cr–Ni alloy was investigated. Fe–Cr–Ni alloy (in initially solution annealed condition) was uni-directionally cold rolled in a laboratory rolling mill to different thickness reductions. Scanning electron microscopy was used to observe the changes in microstructure, while X-ray diffraction was used to investigate changes in crystallographic texture of austenite and ferrite (through changes in orientation distribution function). Crystallographic texture was also simulated using different crystal plasticity models (Full constraint Taylor, relaxed constraint Taylor (lath and pancake) and co-deformation Visco Plastic Self Consistent (VPSC)). With the increase in plastic deformation, there were morphological as well as crystallographic changes in the microstructure. Strong α-fibre (RD//〈1?1?0〉) texture was developed in ferrite, while brass ({1?1?0}〈1?1?2〉) and Goss ({1?1?0}〈0?0?1〉) was dominant in austenite after 80% cold rolling. The formation of brass type texture after deformation has been attributed to the formation of shear bands and presence of strong crystallographic texture in the initial solution annealed material. Both Taylor as well as VPSC models could not capture the changes in texture with deformation accurately. For ferrite: γ-fibre (ND//〈1?1?1〉) and for austenite: Cu ({1?1?2}〈1?1?1〉) component was always present in the simulated textures. Possible reason for this could be the pining effect of interface boundaries and non-incorporation of non-crystallographic shear banding in the Taylor and VPSC models.     

Small-angle neutron scattering study on the cold rolled steel sheets

The effect of cold rolling on the small-angle neutron scattering (SANS) pattern was investigated for low-carbon steels. Several cold rolled steel samples with different reduction ratios and annealed samples after cold rolling were respectively measured by SANS. The cold rolled samples presented anisotropic two-dimensional (2D) SANS patterns. From the 2D SANS patterns two kinds of 1D pattern were calculated: one was for the Q⊥RD (rolling direction), the other for the Q//RD. The scatterer sizes calculated from the 1D patterns by using a model fitting increased with the reduction ratio, for the Q⊥RD section only. The annealed sample presented an isotropic SANS pattern. It can be concluded that the dislocations produced during the cold rolling process accumulated around the precipitates and then caused anisotropic 2D SANS patterns.     

国产纯铁的轧制与再结晶织构

用极固与金相研究工业纯铁的轧制与再结晶织构和组织。热轧后的试样经过两种冷轧方法：(1)压下率为98.8%,与(2)压下率为64.5%,中间700℃熟炼;二次冷轧和压下率63.5%。试样在氢气中分别于(a)650°和(b)1000℃熟炼。第一类材料的轧制织构经测定为(100)[011]+(112)[110]+(111)[112].试样在a与γ区域熟炼后的主要取向为(100)[011]和(111)[112]。第二类材料的轧制织构与第一类相似,惟偏离角度较大。表面与内部织构不同。第二类材料熟炼后的再结晶织构基本上相似,金相组织显出第二次再结晶现象。     

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.