A.Di Schino
,
G.Abbruzzese
,
J.M.Kenny
材料科学技术（英文）
A mathematical model, able to describe the recrystallization and grain growth in metals, has been developed. Taking into account the classical constitutive equations of the Taylor’s theory, the model involves only two free parameters (the dislocation density and the initial number of nuclei). Results from the model are here discussed in comparison with measurements performed on an AISI 304 stainless steel. The predictions of the model are in good agreement with experimental results. As cross check of the model prediction, the independent parameter “dislocation density” was found to properly correlate to the mechanical properties of the steel and to X-ray diffraction measurements, according to Taylor’s and Debye’s relations respectively.
关键词:
Recrystallization
,
null
,
null
Journal of Materials Research
Deformation-induced gamma -> DI-alpha(2) phase transformation was verified to occur in the twin-intersection region of a Ti-45Al-8Nb (at.%) alloy compressed at room temperature. High-resolution image observations of the deformation-induced DI-alpha(2) phase suggested that the orientation relationship between the DI-alpha(2) and gamma phases remained the typical one: (0001)(DI-alpha 2)//{111}(gamma), [11 (2) over bar0](DI-alpha 2)//< 101]gamma. The conversion of stacking sequence from ordered face-centered tetragonal to ordered nonequilibrium hexagonal close-packed structure was accomplished by the movement of a/6 < 11 (2) over bar] Shockley partial dislocations on every other {111}(gamma) plane. Compositional analysis based on energy dispersive spectra revealed that the DI-alpha(2) phase had the same composition as the matrix gamma phase. No compositional diffusion Occurred because the plastic deformation was carried out at room temperature. The strong stress concentration in the intersection region was the major force to induce the gamma -> DI-alpha(2) phase transformation in the process of room-temperature compression.
关键词:
titanium aluminides;mechanical-properties;room-temperature;microstructure;intermetallics;microscopy;nb
徐江华
,
李山青
上海金属
DI材是宝钢的重要产品,主要用于碳酸饮料罐和啤酒罐.DI材沿宽度方向的厚度均匀性要求十分严格.为了减少DI材的横向厚差,开发了横向厚差自动控制系统并应用在某冷连轧机上.该控制系统使用了基于鲁棒性能指标(robustness specification)的横向厚差自动控制算法,从而使厚度0.229 mm以下的DI材的横向厚差被控制在±4μm以内.
关键词:
DI材
,
冷轧
,
横向厚差
,
自动控制
Hu Wang Juan Xie Kangping Yan Ming Duan
材料科学技术（英文）
Different morphologies of zinc oxide (ZnO), including microrods, hexagonal pyramid-like rods and flower-like rod aggregates, had been synthesized, respectively, on glass substrates by controlling the reaction conditions (such as precursor concentration, reaction time and pH value) of hydrothermal method. The morphologies of the as-obtained ZnO were observed with scanning electron microscopy and transmission electron microscopy.
Also, the crystalline natures of di®erent ZnO crystals were analyzed with X-ray diffraction. The possible growth mechanism of ZnO crystals with di®erent morphologies was discussed.
关键词:
Zinc oxide
Y.B. Hou
金属学报(英文版)
In this paper, the PMMA films doped with N,N'-diphenyl-N,N'-di(m-tolyl)-benzidineand rubrene were fabricated by spin coating, and the effect of photooxidation onthe photoluminescence of the doped PMMA thin films was investigated. The resultsshowed that under the irradiation of 350nm UV light, N,N'-diphenyl-N,N'-di(m-tolyl)-benzidine can sensitized rubrene and results in the enhancement in the photooxrationof rubrene. The effect of photooxidation on the photoluminescence from rubrene w asmore obvious. Both lifetime measurement and in situ measurement of photolumines-cence showed that rubrene molecules exist in two chemical surroundings.
关键词:
photoluminescence
,
null
方百友
钢铁
对于低碳铝镇静钢DI材试验及统计分析结果表明,在一定范围内,碳含量增高,材质面内各向异性减小而趋向于均匀化;终轧温度升高,材质面内各向异性值则增大;卷取温度的影响亦具有类似的规律性.拉伸试验和断面金相分析结果进一步证实,较高碳含量和适当的热轧温度可抑制晶粒过分长大,缩小晶粒间差异,达到改善材质面内各向异性的目的.
关键词:
DI材
,
Δr
,
碳含量
,
终轧温度
,
卷取温度
黄琼
,
赵珊茸
人工晶体学报
doi:10.3969/j.issn.1000-985X.2003.03.010
对透辉石-钙长石-拉长石(Di-An-Ab)三元体系在不同降温速度条件下形成的枝晶进行了研究.其中,透辉石枝晶为规则树枝状,主枝和分枝明显;斜长石枝晶呈放射纤维状集合.枝晶形貌随降温速度变快没有明显变化,枝晶晶体结构随降温速度不同而有改变,降温速度减小,透辉石枝晶晶胞参数a值呈增加趋势,b、c呈减小趋势,斜长石枝晶b值呈减少趋势,c值呈增加趋势,两者β值呈增加趋势,但改变不大.随着降温速度增大,透辉石枝晶、斜长石枝晶硅氧骨干中,铝硅比值增大,铝更大程度地替代硅.另外还发现,降温越快,枝晶结晶数量越少.
关键词:
Di-An-Ab体系
,
枝晶
,
降温速度
,
枝晶形貌
郭颖
,
赵珊茸
,
刘慧芳
,
蒋宏
人工晶体学报
doi:10.3969/j.issn.1000-985X.2005.04.017
对钠长石(Ab)-钙长石(An)-透辉石(Di)三元体系跨相界线的不同成分点在不同的降温速度条件下快速结晶形成的枝状形貌进行了研究.透辉石为枝晶,斜长石为球粒晶.当降温速度慢于1℃/min后,枝状形貌变为板-柱状形貌(即近平衡形貌).我们的实验结果中没有观察到如E.Brener 和H.Muller等人提出的形貌演化图一样的演化规律.当成分点靠近同结线后,出现两晶共结形成的"中空结构".通过光学显微镜下测试其光学性质发现,透辉石沿c轴方向延长,斜长石沿a轴延长,与晶体结构中的强键链方向一致,即快速结晶时晶体沿着结构中负离子配位多面体共角顶、共棱形成的强键链方向生长形成枝体.
关键词:
Di-Ab-An体系
,
枝状形貌
,
各向异性
,
结晶学方向
