晶带轴

On the basis of twin-roll thin strip continuous casting experiments and solidification structure characteristic analysis of thin strip and combining with the simulation results of effects of technological parameters, the forming mechanism of solidification structure zone (especially equiaxed crystal zone) on 1Crl8Ni9Ti stainless steel twin-roll thin strip was investigated.

在双辊薄带连铸实验和薄带凝固组织特征分析的基础上，结合对薄带凝固组织区的模拟预测结果，研究了1Cr18Ni9Ti不锈钢双辊薄带凝固组织区的形成机理。结果表明：1Cr18Ni9Ti不锈钢双辊薄带凝固组织中的等轴晶区不但在凝固类型为半固态时形成，在轧制或理想型时也能形成。其形成机理为，熔池中悬浮游离晶体的沉积、聚集以及在枝晶生长前沿的长大和薄带离开二铸辊最小间隙后，薄带/空气界面换热系数骤然降低抑制了柱状枝品的生长，并促使薄带中部未凝固熔体中游离晶体的择优长大

In the simulation, the flow rule of melt metal in mold of horizontal continuous casting with electromagnetic stirring is measured using ultrasonic Doppler velometer, and the result is inter confirmed with the solidification characteristics is tics of zinc cupronickel thin slab in industrial product, some advantageous results are obtained that, when the current is 400 A the inner micro-pores disappear, when the current is 500 A the center equiaxed crystal layers occur and when the current is to 800 A the inner-segregation decreases to zero.

在模拟实验中，用超声波多普勒测速仪测量该电磁搅拌下水平连铸结晶器内金属液的流动规律，并与生产实验中锌白铜板带的凝固特征相互印证，发现搅拌电流达到400 A时，板带内部气孔消失，电流达到500 A时板带出现等轴晶带，电流达到800 A时板带坯偏析率趋于零。

This demonstrates that the formation and the growth of the crystal texture in the a-Fe/Nd2Fe14B nanocomposites result from the large temperature gradient normal to the free surface of the ribbons during the process of rapid solidification.

在激冷面各晶面法线方向的尺寸相近，表明纳米晶的形状近似于等轴晶。a-Fe/Nd2Fe14B纳米晶织构的形成和生长受合金薄带在凝固过程中热流梯度的控制。

Moreover, the hot compressive deformation behavior of the RS/PM AZ91 magnesium alloy and AZ91 alloy matrix composite were also investigated, the conclusions are drawn as follows:1. The processing parameters of the atomization-twin rolls quenching technology were optimized as follows: the diameter of the nozzle 1mm, the wheel velocity 25m/s, the pressure of atomization gas 0.3MPa and Ar gas for melt injection 0.1MPa. The RS AZ91 alloy flakes exhibited fine and uniform microstructures. When the flakes were extruded at 673K, extruded velocity of 0.1mm/min and extrusion ratio of 25:1,the magnesium alloy rods with clean surface, uniform dimension and excellent mechanical properties were obtained.2. The RS AZ91 magnesium alloy powders prepared by atomization-twin rolls quenched technology exhibited fine equiaxed grains with the grain size of 1-3μm, the phase constituent included supersaturate solid solution phaseα-Mg and miner fineβ-Mg_(17)Al_(12) phase. The as-extruded materials also exhibited equiaxed grains with the size of 5-7μm and a large number of fineβ-Al_(12)Mg_(17) and fewer AlMg_2Zn phases were detected in the alloy.

本文还研究了快速凝固/粉末冶金AZ91镁合金热压缩变形流变应力行为，快速凝固/粉末冶金法原位生成Mg_2Si增强AZ91镁基复合材料，经过系统的研究，获得如下结论：1、雾化-双辊急冷法在下列工艺参数组合下：双辊线速度25m/s；喷嘴直径1mm；熔体压射压力0.1MPa；雾化气体压力0.3MPa。，可获得宏观尺寸细小、微观组织均匀细小、综合性能优良的的快速凝固AZ91镁合金细碎箔带，快速凝固箔带在挤压温度为673K、挤压速度为0.1mm/min，挤压比为25：1时，可获得的外表光洁、尺寸均匀、组织性能优异的镁合金棒材。2、雾化-双辊急冷法制备的AZ91镁合金粉末态为细小等轴晶组织，晶粒尺寸1-3μm，组织为α-Mg过饱和固溶体和微量的细小β-Mg_(17)Al_(12)相组成；粉末挤压棒材为等轴晶组织，晶粒尺寸5-7μm，组织中含有大量细小的β-Al_(12)Mg_(17)以及AlMg_2Zn析出相，室温力学性能，抗拉强度383MPa，屈服强度275MPa，断后伸长率7.5%。

The tectonic rocks along the fault zone are composed of cataclastic rocks and mylonites formed in higher, middle and lower temperature. Respectively, both of structural features and rocks have the features of multiple phase's of deformation. The deformation features of main minerals in the high temperature mylonites show that: the quartz has the form of long single crystal and the fabric feature of point maximum near X axis; the feldspar has the form of recrystallization assemblage, They present a high amphibolite-granulite facies with temperature ＞600℃ and depth ＞20km. The deformation features of mylonites formed in middle temperature show that: the quartz has the form of polycrystal banding and the fabric feature of point maximum near Y axis and small circle girdle with Y rotational axis; the feldspar has the form of a coremantle structure, They reflect a high greenschist-lower amphibolite facies with temperature from 400℃ to 600℃ and depth from 15km to 20km.

其中，高温糜棱岩主要矿物变形特征组合为：石英为长矩状或长条状单晶、组构为近X轴的点极密，长石为几乎完全重结晶的集合体，形成温度＞600℃，相当于高角闪岩—麻粒岩相，形成深度＞20km；中温糜棱岩主要矿物变形特征组合为：石英为多晶条带、组构为近Y轴点极密和以Y轴为旋转轴的小圆环带，长石发育核幔结构，形成温度为400～600℃，相当于高绿片岩—低角闪岩相，形成深度为15～20km；低温糜棱岩主要矿物变形特征组合为：石英发育核幔结构、组构特征为近Z轴点极密，长石以碎裂为主，形成温度＜400℃，相当于中低绿片岩相，形成深度为8～12km；碎裂岩则主要代表了地表浅层的变形。

Based on the research on the solidifiation of twin-roll casting strip,the analytical model and emulational model of nucleation,the growth of dendrity tip and colunar dendrity transformation to equiaxis dendrityof twin-roll casting strip solidification are established by means of the principle of metal solidification and modern computer emulational technology.

在研究双辊薄带连铸工艺凝固过程的基础上，运用金属凝固的基本原理，并用现代计算机仿真技术建立了双辊连铸薄带凝固的形核、枝晶尖端的生长动力学、柱状晶向等轴晶生长的转变的解析模型及仿真模型，为双辊连铸薄带凝固组织形成的仿真模拟奠定了基础。

It was found that more segregations of C, P, S and Mn occurred at the boundaries between the columnar grains and equiaxed grains.

研究中发现，在铸坯柱状晶与中心等轴晶带的边界处，C、F、S、Mn发生较大的正偏析。

Experimental results show that rapid solidification technology can remarkably optimize Mg-Zn-Nd alloy's microstructure and property,there are three zones of fine grain zone,columnar grain zone and equiaxial grain zone in ribbon's solidification structure,which reserve structure character of cast-magnesium alloy.

结果表明：快速凝固技术可显著优化Mg-Zn-Nd合金的组织结构与性能；薄带的凝固组织分为细晶区、柱状晶区、等轴晶区三个区域，保留了铸态凝固组织的特性；快速凝固技术的细晶强化和固溶强化可明显改善Mg-Zn-Nd合金的强度与塑性。

The orientation tiltings were suggested to be one of the inportant mechanisms by which GaN films could match better with Al2O3(0001) substrates and relax the interfacial strain effectively.

GaN绕〈1120〉晶带轴倾斜的匹配方式是其外延生长过程中降低和Al2O3(0001)的晶格失配、释放界面应变的重要机制之一。标签 GaN Al2O3(0001)衬底 MOCVD 晶格匹配 GaN Al2O3(0001) substrate MOCVD lattice matching

The error analysis shows that the present indexing method seems to be available to the cases of the zone axis both parallel and inclined to the optical axis of SEM.

误差分析表明，本注释方法不但适用于晶带轴平行于扫描电镜光轴的情况，而且适用于晶带轴倾斜于光轴的情况。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。