Ti60合金棒材中的织构及其对拉伸性能的影响

将a+b两相区精锻,直径为30和45 mm(分别定义为D30和D45)的Ti60棒材分别在950,1000和1050℃进行固溶+时效热处理,研究了热处理温度对棒材织构和拉伸性能的影响.结果表明,D45棒材锻态组织中,棒材轴向与a相的0001或101ˉ0方向平行的丝织构较强;950℃热处理后显微组织和织构变化不明显.随固溶温度升高,a相的0001丝织构增强,而101ˉ0丝织构密度减弱.固溶温度对棒材强度的影响不大.D30棒材锻态组织中主要存在101ˉ0方向的丝织构;随固溶温度升高,0001丝织构逐渐增强,棒材的室温强度显著升高.     

Ni_(47)Ti_(44)Nb_9合金丝材织构、记忆恢复应变及其理论计算

利用取向分布函数(ODF)研究了Ni47Ti44Nb9(原子分数)合金丝材的织构。结果表明,织构由锻棒的111丝织构转变为丝材的113、112丝织构。由ODF回算的反极图数据,根据晶格畸变理论法计算了丝轴方向的记忆恢复应变,经实验证实,计算的结果与实测结果趋势一致,随变形量增加,先升后降。     

拉拔过程中珠光体钢丝心部的织构演化规律及其对力学性能的影响

采用电子背散射衍射(EBSD)技术研究了拉拔过程中珠光体钢丝心部织构演变规律.结果表明,经过多道次干拉和淬火处理的钢丝存在强度较小的110丝织构,经过湿拉拔后,110丝织构强度明显增加.应用黏塑性自洽模型(VPSC),建立了拉拔过程中钢丝心部织构计算模型,预测了织构的演化规律,并用虚拟的单向拉伸实验研究了初始织构对力学行为的影响.预测结果与EBSD测试结果相符,随着拉拔应变的增加,晶粒的110取向逐渐转向拉拔方向.在拉拔方向上的反极图中,存在113和012连线上稳定的取向,靠近001和111连线上的取向先转向到稳定取向再转向110取向,其它取向直接转向110取向.随着拉拔应变增加110丝织构的体积分数逐渐增加,增加速率逐渐减小.随着初始110丝织构体积分数的增加钢丝心部的屈服应力逐渐增加.     

横轧3 104铝合金变形织构的研究

应用极图分析及织构定量计算的方法，研究了横轧对3104铝合金变形织构的影响，结果表明：在与常规轧制相同压下量的横向轧制下，3104铝合金中的｛112｝，｛213｝丝织构体积百分数均低于常规轧制时各组分的体积百分数，而横向轧制则使得｛102｝丝织构增加较多，在横向轧制过程中出现强旋转立方织构和新｛110｝＜557＞取向的织构。     

挤压镁合金AZ31的压缩过程中的组织及织构演化

对常规挤压态镁合金AZ31压缩过程的组织及织构演化进行了扫描电镜-电子背散射衍射(SEM-EBSD)原位观察。结果表明材料的初始组织为等轴晶,晶粒的平均尺寸为76微米,晶粒内部未发现形变孪晶。材料的初始织构类型为典型的{11-20}丝织构,即大多数晶粒的<11-20>晶向平行于棒材的挤压方向(ED)。在压缩过程中,多数晶粒内部开始出现拉伸孪晶,随着压缩应变的增加,孪晶片层不断增厚,导致晶内的孪晶合并成大的孪晶并占据晶粒内部的大部分区域进而使孪晶的体积分数不断增加。随着压缩压缩应变的增加初始丝织构不断减弱并有新的基面织构形成。实验表明压缩过程中的{10-12}<10-11>孪生而非滑移是引起压缩过程中织构演化的主要原因。     

激光增材制造钛合金织构跨尺度分析

针对增材制造钛合金的组织特点,采用EBSD以及XRD的方法对增材制造TC11合金进行了织构分析,探讨TC11合金从微米级微观织构到厘米级宏观织构的变化规律,分析了EBSD扫描面积大小对织构分析结果的影响。结果表明,采用大面积EBSD拼接扫描的织构分析结果与XRD宏观分析结果一致。TC11合金β相具有001∥沉积方向的丝织构及弱(001)[010]板织构,α相的主织构为160 16 19∥[001]、2110∥[001]丝织构。     

面心纯铝单向拉伸的晶体塑性学有限元模拟

基于率相关晶体塑性本构模型,实现了晶体塑性学有限元模拟过程。直接将电子背散射衍射(EBSD)获取的晶粒初始取向输入晶体塑性有限元模型,分别预测了单向拉伸面心1050纯铝过程中的力学响应与织构演化。应力应变响应数值模拟结果与实验结果有较好的一致性,同时也存在一定的偏差。两种多晶模型(Taylor模型和有限单元模型)分别模拟了单向拉伸真应变0.25和0.37时的织构演化。随着真应变的增加,两种丝织构(〈111〉织构和〈100〉织构)变得更加锋锐,模拟结果与EBSD实验测得的织构演化结果有较好的一致性。     

Ti-2Al-2．5Zr钛合金丝材的普通退火工艺

研究了退火温度对Ti-2Al-2.5Zr钛合金丝材力学性能、显微组织的影响规律,并分析了该合金丝材退火后的织构.结果表明,在相变点之下,合金力学性能、显微组织只与再结晶有关;经(700～750)℃×1h·AC的真空退火,可获得均匀细小的等轴组织,强度、塑性达到最佳匹配.在相变点之上,获得锯齿状的粗大晶粒,强度较高,而塑性较差.退火后可获得两种织构,一种为在相变点之下,经完全再结品退火可获得2,-1,-1,0丝织构;另一种为在相变点之上获得,该织构除了具有前一种丝织构外,还具有相对较弱的2,-1,-1,3丝织构.     

退火温度对冷拔钢丝织构与性能的影响

采用精确的线材织构测定方法分析了冷拔钢丝在450、550和650 ℃退火过程中织构变化,并采用光学显微镜和显微硬度计研究了此过程中钢丝的显微组织和显微硬度。 结果表明：冷拔钢丝在不同温度下退火过程中,随着退火温度的升高,显微组织由纤维状转变为等轴晶,硬度显著下降;不同温度退火后的织构与拉拔态的织构类型相同,以<110>丝织构为主,且沿着线材径向呈现一定梯度分布。 但是随着退火温度的升高,<110>丝织构强度下降。另外,退火过程中,冷拔钢丝的硬度与<110>丝织构强度具有相似的变化趋势。     

异步轧制高纯铝箔冷轧织构沿板厚的分布规律

通过异步轧制，研究了高纯铝箔冷轧织构沿板厚的分布规律。在异步轧制下，快、慢速辊侧之间的各中间层的织构类型不同。速比为1．28，形变量为99．2％时，随厚度的增加，呈现出极有规律的变化：（100）丝织构含量近线性减少，而（112），（102），（123）丝织构含量近线性增加。当形变量为99．2％时，在不同速比下（400）丝织构含量沿厚度变化趋势不同：速比1．28时，呈现出近线性递减；速比1．17和1．06时，总的趋势也是递减，且在厚度d＝0．04mm处有最小值。     

Structure and microhardness of rapidly solidified foils of binary indium alloys

Structure of indium and binary indium-based alloys obtained by rapid solidification has been investigated. In the rapidly solidified foils of indium and its binary alloys with tin, lead, bismuth, zinc, and antimony (to 0.6 at %), there is formed a (101) texture, and in the alloys that contain a higher concentration of antimony, an (001) texture. The foils of the alloys that contain to 4 at % bismuth, lead, and cadmium and to 8 at % tin are single-phase. In the foils of the alloys containing zinc and antimony, dispersed particles of zinc and indium antimonide are precipitated.     

涂层导体用织构铜镍合金基带热处理工艺的研究

铜镍合金基带是制备双轴织构钇钡铜氧(YBCO)涂层超导体的优良合金基带之一。采用轧制辅助双轴织构基带技术(RABiTS)制备无磁性的CuNi金属合金基带。采用X射线衍射技术(XRD)及背散衍射技术(EBSD)对CuNi合金基带再结晶热处理后的织构表征分析发现,热处理工艺是影响合金基带再结晶晶粒取向的重要因素之一。结果表明,对CuNi合金基带进行950℃下保温60min的最佳热处理工艺后,CuNi合金基带表面形成了锐利的立方织构,其立方织构的含量高达97%(≤10o)。     

Behavior of oxygen diffusion in buffer layers for coated conductors

We have evaluated the effect of annealing in oxygen atmosphere on the structure, texture and phase transformation of LZO films deposited on YSZ (yttria-stabilized zirconia) (0 0 l) single crystal substrates and textured NiW substrates by metal-organic deposition (MOD) method. The results show that the structure stability of the LZO films is heavily dependent on the oxygen partial pressure in annealing process. Then we have in details studied the behavior of oxygen diffusion in three kinds of buffer layer architectures on NiW substrates by varying the temperature, oxygen partial pressure and dwelling time in the annealing process. The oxygen diffusion within buffer layers leads to the oxidation of substrate, and even the texture and structure of buffer layers are destroyed with the increase of the thickness of the oxides layer related to NiW substrate. It reveals that the relative volume of oxides related to NiW substrate increases exponentially with the annealing temperature, and increases linearly with the annealing time at logarithmic scale. The relative intensity of texture peaks of buffer layers decreases and even disappears with the increase of the oxygen partial pressure in annealing process because of the acceleration of the oxidation reaction of substrate. The influence of annealing temperature, oxygen partial pressure and dwelling time on the oxygen diffusion is related to the intrinsic oxygen diffusion coefficient of buffer layers materials. Compared with the increase of oxygen partial pressure, the elongation of dwelling time shows a less effect on the oxidation rate of NiW substrate and a weak destruction of the texture of buffer layers. Except choosing the oxide materials with small oxygen diffusion coefficient as buffer layers in coated conductors, the degree of oxidation about NiW substrate could be greatly controlled and it would result in the less destruction of texture and structure of buffer layers by adjusting the annealing temperature, oxygen partial pressure and dwelling time in the process of YBCO deposition.     

Development of roping in an aluminum automotive alloy AA6111

The roping behavior of an automotive sheet alloy AA6111 was investigated for two processing schedules that led to the production of: (1) roping and (2) non-roping materials. In contrast to the data available in the literature, this study shows that both ridges and valleys on the upper and lower surfaces are irregularly distributed in the rolling direction (RD) and that ribbed profiles and corrugations are rare. The electron back scattering diffraction (EBSD) experiments demonstrated that banded structures of Goss are more evident throughout the specimen thickness than similar bands of Cube texture. The volume texture of the hotband comprised of the strong brass–copper–S fiber, while exclusively Cube texture was present in the non-roping material. In addition to the Cube, the Goss, G1, S and [100]//RD fiber components were produced in specimens associated with roping. The present study shows that the spatial distribution of the Goss component is responsible for the roping behavior in aluminum alloy AA6111.     

Ti-IF钢罩式退火过程中再结晶织构演变规律研究

采用X射线衍射技术(XRD)和电子背散射衍射技术(EBSD),并结合微观组织观察分析了Ti-IF钢罩式退火过程中织构演变规律和{111}再结晶织构形成机制.结果表明:随退火温度的升高,再结晶量逐渐增多,{111}再结晶织构强度亦逐渐增强,同时{100}织构强度逐渐减弱.{111}取向的品粒主要在再结晶过程中形成,依靠吞并其他取向[主要是{100}取向]的晶粒而长大;并且在{111}取向品粒长大过程中,γ纤维织构之间也发生相互转化,主要由{111}<112>织构转变为{111}<110>织构;冷轧IF钢再结晶退火后具有较强的γ纤维织构,主要是"取向形核"和"取向长大"共同作用的结果,其中Σ重位晶界在再结晶γ纤维织构形成过程中起着重要作用.     

脉冲电流轧制对AZ31镁合金微观组织与力学性能的影响

对比研究脉冲电流轧制工艺与温轧工艺对AZ31镁合金板材的力学性能、织构、微观组织与沉淀相等方面的影响。结果表明：脉冲电流具有促进冷轧AZ31镁合金低温再结晶能力的作用。脉冲电流轧制后的镁合金板材组织由细小的等轴再结晶粒与析出相构成,没有发现孪晶组织,并且完全再结晶,原始晶粒均被细小的再结晶晶粒取代,再结晶晶粒内的位错密度低。而温轧镁合金组织则由稍拉长变形孪晶、粗大的再结晶晶粒和析出相构成,再结晶的晶粒内位错密度高。两种轧制方式下的镁合金析出相均为Mg17Al12。脉冲电流轧制后镁合金的织构具有典型基面织构的特征,而脉冲电流轧制镁合金的织构则出现横向偏转;脉冲电流轧制后镁合金的屈服强度与伸长率均比温轧镁合金的大,但抗拉强度正好相反。     

Microstructure and Properties of Deformation Processed Polycrystalline Ni47Ti44Nb9 Shape Memory Alloy

The objective of this work was to investigate the relationships between process and microstructure and property in polycrystalline Ni₄₇Ti₄₄Nb₉ alloy. Three processes: (1) hot-forged, (2) cold-drawn, and (3) cold-rolled were investigated. The microstructure was tested by means of optical microscope, x-ray diffraction, and electron backscatter diffraction, and then crystalline orientation distribution functions and inverse pole figures were measured. The results indicated that hot-forging eliminated dendritic microstructure and fined the eutectic structure. It also induced a 〈113〉 fiber texture, which paralleled to the axial direction. The cold drawing and cold-rolling had a further effect in grain refinement. And the cold-drawn specimens contained a strong 〈111〉 fiber texture paralleling to the deformation direction, while the cold-rolled tubes formed 〈111〉 crystalline directions paralleling the axial direction and 〈110〉 crystalline directions of crystalline arranged along the circumferential direction. The notably distinctive recoverability of different processed materials was observed and discussed.     

Q235碳素钢应变强化相变过程中铁素体晶粒取向分析

利用Ｘ射线衍射和背散射电子衍射（ＢＳＥＤ）分析了单向热压缩条件下碳素钢Ｑ２３５应变强化相变产生的铁素体及 先共析铁素体在应力作用下的晶粒取向分布特点,结果表明,通过应变强化相变产生的铁素体晶粒取向并非完全随机分布,而有较 强的（１１１）／／ ＮＤ线织构 这明显不同于形变铁素体和部分动态再结晶的铁素体晶粒取向待征,先共析铁素体的相对量与（１００） ／／ＮＤ线织构的强度对应。ＢＳＥＤ局部取向（差）定量分析表明,（１１１）取向既可来自应变强化相变,也可来自形变的先共析 铁素体。虽然先井析铁素体形变后外形为形变长条状,但内部仍存在一定的大角晶界;表明先共析铁素体在大应变下进行了一定程 度的动态再结晶     

Kinetics of picosecond laser treatment of silver nanoparticles on ITO substrate

In this work, the effect of ITO substrate on Ag NP size, morphology and photoinduced absorption depending on the time of 30 ps laser treatment were explicitly studied. Silver nanoparticles with an average diameter of ∼40 nm supported on indium tin oxide (ITO) were irradiated with a tightly focused pulsed laser (doubled frequency beam) at 532 nm. The size transformation of silver nanoparticles induced by a single pulse of Nd:YAG laser (λ = 532 nm, pulse width = 30 ps) was directly observed by an electron scanning microscopy (FE-SEM) on indium tin oxide surface. Simultaneously the change in the absorption and the corresponding derivatives are also presented. These morphological changes are accompanied by a significant change in the optical absorption properties of the array. This study demonstrates that picosecond laser irradiation is an excellent technique to operate and control the properties of nanostructured materials on solid supports.     

具有重叠衍射峰低对称晶系材料的定量织构分析

本文给出了具有重叠衍射峰的低对称晶系材料织构定量分析的最新细化方法：将熵最大原则直接引入到以极图数据为约束条件的最小二乘方程中，实现了最小极密度差与熵最大两种优化的同步进行，四方晶系材料的纤维织构模拟例子表明：即使在很锐的织构组分时，依据本文的方法也可以从较少数目极图数据获得准确的织构矢量．