FeCuNbBSi等多中Fe基非晶态合金激波晶化的DSC研究

应用升温、等温和重复加热的DSC技术，对几种非晶合金的激波晶化和退化晶化作了对比研究，结果表明，尽管激波晶化时间极短，仅为退火晶化时间为10^-6－－10^-8，但晶化度却极高，接近100％。激波晶化形成多种成分和结构的结晶相，形式上很像扩散性相变，然而其相变速率却是退火转变的千万倍，而且生成相十分稳定，这一现象用传统的固态扩散相变理论很难解释，激波晶化是一种新的晶化形式，是一种新的纳米合成技术。     

非晶合金Fe73.5Cu1Nb3Si13.5B9的激波晶化及其特征

 研究了非晶合金Fe_73.5Cu₁Nb₃Si_13.5B₉（FINEMET）的激波晶化。与退火晶化比较,激波晶化具有一系列鲜明特征,这些特征是固态下扩散性相变理论难以解释的,有深刻的物理内涵。     

Fe78B13Si9、(Fe0.99Mo0.01)78B13Si9非晶合金的激波晶化实验研究

 研究了Fe₇₈B₁₃Si₉、(Fe_0.99Mo_0.01)₇₈B₁₃Si₉非晶合金的激波晶化行为。激波是由氢-氧爆炸产生的。实验结果表明：激波能使非晶合金在微秒时间内晶化,晶化主相为α-Fe基固溶体,次晶化相为Fe₃Si,且观察到α-Fe基因溶体晶格常数变小。用DTA分析进一步证实：激波晶化是比较完全的,晶化相相当稳定。     

Fe73.5Cu1Nb3Si13.5B9非晶合金的激波纳米晶化速率和晶化度的对比研究

对Fe73.5Cu1Nb3Si13.5B9等非晶合金进行了退火和激波诱导两种方式的晶化实验以及XRD和DSC分析.着重对合金的晶化速率和晶化度等特性展开了研究和讨论.进一步证实了激波纳米晶化是一种包含着新机理的寓意丰富的晶化现象.也再次验证了作者曾经提出过的"激波流化相变"模型的合理性.     

Fe73.5Cu1Nb3Si13.5B9非晶合金的激波纳米晶化速率和晶化度的对比研究

对Fe735Cu1Nb3Si135B9等非晶合金进行了退火和激波诱导两种方式的晶化实验以及XRD和DSC分析.着重对合金的晶化速率和晶化度等特性展开了研究和讨论.进一步证实了激波纳米晶化是一种包含着新机理的寓意丰富的晶化现象.也再次验证了作者曾经提出过的“激波流化相变”模型的合理性. 关键词： 非晶合金 激波 纳米晶化     

静高压下Al-Mn准晶形成及其结构稳定性的研究

 静高压（4.5 GPa）下Al₆Mn合金熔态淬火（冷却速度约为10² ℃/s），得到Al₆Mn合金的高压淬火样品。X射线分析表明：Al₆Mn合金的高压淬火样品中含有准晶二十面体相、Al₆Mn相及Al的面心立方相；与常压结果相比，高压淬火方法的冷却速率可比常压的低约3个数量级的条件下产生准晶二十面体相。其晶化温度与急冷甩带的相近。对静高压（2.5 GPa）下Al₆Mn准晶条带样品的晶化过程进行了研究。X射线分析表明：静高压下Al₆Mn准晶条带样品的晶化过程中，出现了一种新的未知亚稳相——准晶向晶体转化中的一种中间过渡态，具有类T相形式；与常压结果比较，高压下准晶相晶化温度提高。     

几种铁基非晶合金激波诱导晶化中的若干奇异物理效应研究

应用x射线衍射、透射电子显微镜和差示扫描量热实验技术，研究了FeCuNbBSi，FeBSi，FeMoBSi几种铁基非晶合金的激波诱导晶化.研究结果表明：非晶态合金激波诱导晶化中存在若干应用传统长程扩散相变理论难以解释的奇异物理效应.用非晶态合金激波流化晶化可以很好地解释激波诱导非晶晶化中的各种奇异物理效应. 关键词： 激波晶化 非晶态合金 激波流化 流体扩散     

PVDF在电子束辐射材料产生的热激波测量中的应用

 介绍了在“闪光二号”脉冲电子束加速器上采用PVDF压电传感技术测量编织材料等的电子束热激波传播特性的情况。实验得出：（1）在能注量为90～210 J/cm²范围内，对4 mm厚的编织材料及其叠层材料，热激波应力峰值σ_a<0.1 GPa，只有硬铝的十几分之一；（2）编织材料中的热激波作用时间被明显展宽，其平均值达2.6 μs，是硬铝中的7倍多。实验结果表明：（1）编织材料具有良好的衰减和展宽热激波的性能；（2）对编织材料等的宽作用时间热激波测量来说，PVDF压电传感技术具有极其优越的性质。     

Cu100-xZrx金属玻璃压缩率及压力感生晶化现象

 本文采用金刚石对顶压砧高压装置和高压X射线技术测定了两种金属玻璃线压缩率曲线；得到Cu₃₀Zr₇₀和Cu₂₅Zr₇₅的线压缩率分别为2.7×10^-3 GPa^-1和2.3×10^-3 GPa^-1，实验最高压力超过30 GPa。实验过程中首次观察到Cu-Zr金属玻璃在室温下加压发生晶化的现象。     

关于2024Al液-汽临界性质

 考查了冷压p_0K为A(δ^B-δ²)形式物态方程的临界性质，提出了两种修正的Morse势冷压形成，并计算了其临界参数，认为这是一种较合理的形式。分别对电子比热系数β_0K=0和β_0K≠0计算了液-汽相变平台。     

Atomistic investigation of phase transition in solid argon induced by shock wave transmission

A molecular dynamics (MD) simulation is employed to study the phase transition process in argon induced by shock wave transmission. Deriving the relation between the shock and piston velocities, the theoretical equation of state for argon is presented. Also, argon equation of state is obtained by measuring the quantities directly from simulations to be able to detect the phase transitions. The phase transition is also detected by using argon phase diagram and free energy calculations. A comparison shows good agreement between the theoretical and MD results for the phase transitions. Based on these simulations, it is concluded that under a shock wave transmission with suitable energy, the solid argon experiences a phase transition from solid to liquid and another from liquid to supercritical fluid. By reflecting the shock wave back at the end of its passage, the whole argon may reach the supercritical state.     

铁的冲击相变机制的分子动力学研究

 用分子动力学方法模拟计算了在冲击波加载条件下,单晶铁中的结构相变（由体心立方结构α相到六角密排结构ε相）,相互作用势采用铁的嵌入式原子势（EAM）,单晶铁样品的尺寸为28.7 nm×22.9 nm×22.9 nm,总原子数为1.28×10⁶个。通过推动一个运动活塞对静止靶的作用来产生冲击压缩,加载方向沿单晶铁的[100]晶向。通过对原子位置的追踪,揭示了铁的冲击相变机制,计算结果表明相变机制包括两步：首先是在{011}面上的原子受到沿〈100〉晶向的压缩,使{011}面转化成正六角形密排面;然后是在{011}面上原子沿〈0-11〉晶向的滑移,完成由bcc结构到hcp结构的相变。同时发现滑移面只出现在与冲击波加载方向平行的(011)和(0-11)面上。     

一种新的氮化碳相的冲击波合成

 为了合成理论预测存在的高密度氮化碳相,以富氮的C-N-O非晶材料和晶态的双氰胺为前体,在低于50 GPa的冲击压力范围内进行了一系列冲击回收实验。回收产物的XRD衍射表明,形成了由β-C₃N₄和一种新的氮化碳相组成的复合相。该新相的衍射峰可以完全指标化为一个单斜晶胞,晶胞常数为a=0.981 nm,b=0.723 nm,c=0.561 nm,β=95.2°,晶胞体积V_cell=0.396 6 nm³。根据实验结果可以认为,氮化碳复合相的形成是前体有机分子在瞬态的冲击波化学反应后,经历了极高速的冲击淬火过程（约10⁹ K/s）,作为一种高压亚稳相而被保存下来。冲击压缩富氮的有机物前体,是合成氮化碳相的一种新方法。     

Shock-induced crystal-glass transition in solid silica

Solid silica SiO₂ occurs under a variety of forms, α-quartz being the stable one at ambient conditions. Shock wave compression induces in this mineral typical defects which appear at the optical microscope as very straight and narrow (≤1μm) lamellae parallel to {10 n} planes. Transmission electron microscopy on both naturally (meteorite impacts) and experimentally (gun shots) shocked quartz shows that they are thin lamellae of amorphous silica. Theoretical computations show that the shock-induced crystal-amorphous transition results from instabilities of the shear modulus in {10 n} planes for P>10 GPa. The elastic misfit energy in the shock front is relaxed by the nucleation of amorphous and more compressible zones the growth of which is then driven by the propagating shock front. The boundaries delineating these defects are sharp and move at very high speed.     

冲击加载下PZT-95/5陶瓷铁电－反铁电相变实验研究

 用石英计测量了PZT-95/5陶瓷在冲击波作用下发生铁电－反铁电一级相变时产生的双波结构，相变起始压力约为0.5 GPa。对不同状态下的PZT-95/5陶瓷材料进行了扫描电镜电畴分析，结果表明，在该压力区域陶瓷发生了铁电－反铁电相变。     

冲击波温度和压力对二氧化钛相变的影响

 介绍了一种简便易行的降低疏松固体物质冲击波温度的方法，其要点是用液体石蜡充填样品的空隙。以用粉末锐钛矿压装成型的样品为例，对比了不充填和充填液态石蜡时冲击波作用的结果。在同样的冲击加载条件下（均为钢飞片，撞击速度为3.16 km/s），估算两种样品中达到的压力分别为36.3 GPa和46.8 GPa，平均温度分别约为4.7×10³ ℃和2.0×10³ ℃，即：充填液态石蜡的样品中压力增加了约10 GPa，但平均温度降低了近3×10³ ℃。对冲击后回收样品的分析结果表明，不充填石蜡样品的主要产物为金红石，即冲击波产生的高温起了主要作用。而充填液态石蜡时，主要生成β-TiO₂高压相，即高压起了主要作用。     

Shock wave chemistry

Abstract

Shock wave chemistry, a new scientific trend, deals with investigations of chemical aspects of the substance state under this new type of effect. Indeed, shock wave effect is not a greater imposition than pressure and temperature actions. Characteristic features of the effect are the tremendous rates of substance loading and subsequent unloading. The effects result in a substance in a strongly non- equilibrium state. The lifetime of the state is governed by the relaxation process of those phenomena which are provoked by shock waves in the substance. For instance, in the case of substance consisting of complex molecules with a large number of internal degrees of freedom, differing strongly in excitation times, all kinetic parts of the shock energy are at first absorbed by the translational degrees of freedom inside the shock wave front. Then, the energy is redistributed to the vibrational degrees of freedom. The non-equilibrium state time is not longer than the excitation time of the most slowly excited vibrational degrees of freedom (10¹⁰-10^?9 s). The same order of magnitude is the relaxation time of liquid substance polarization caused by dipolar molecules mechanically turning under the shock discontinuity zone effect. In polymers the zone turns some separate groups of polymer molecule atoms. In such a case the relaxation period, on the contrary, may last as long as it can. As far as “hot are concerned, their lifetime is determined by thermal relaxation regularities and it depends on their size. The hot spots in solids appear during the shock compression process at the sites of an imperfect substance structure. In liquids the hot spots can orighate when a shock wave front passes through negative density fluctuations. It transforms the fluctuations of very small size and of high probability into some positive temperature regions of large size and extremely low probability at equilibrium state behind the wave front. The hot spots in perfect solids (possibly in liquids too) appear due to the effect of shear stresses in shock front. Pointed and lengthy defects of solid structure occur under the effect. The lengthy defects appear in the shock wave front due to the transition from one-dimensional to volume compression. The transition takes place if the wave intensity is larger than the dynamic elastic limit of the solid under investigation. In brittle materials the transition results in their grinding into fragments and in the relative displacement of the fragments. Some liquid melted layers of substance appear between the fragments in the process of displacement. Their lifetime is also determined by the thermal relaxation regularities and probably is small. Nevertheless, the layers obviously govern the spall strength of brittle solids and promote solid-phase shock reactions. The defects created in solids by the shock effect can exist for a very long time if the solid substance residual temperature is lower than its recrystallization temperature. Therefore, solid substance treatment by shocks of proper intensity can increase their chemical reactivity.