Fe40Ni40P12B8非晶合金的冲击晶化实验研究

 本文研究了Fe₄₀Ni₄₀P₁₂B₈非晶合金冲击波加载下的晶化行为，冲击波由二级轻气炮发射的告诉弹丸撞击靶产生。实验结果表明：Fe₄₀Ni₄₀P₁₂B₈非晶合金在冲击波加载下，晶化可在加载时间（微秒量级）内发生；晶化的阈值压力在30~50 GPa之间，相应的冲击温度约为510~800 K，晶化析出相与冲击压力有关，低压下析出相是面心立方γ-(Fe, Ni)固溶体和Fe₃(P_0.37B_0.63)化合物，高压下（大于60 GPa）析出相除了面心立方γ-(Fe, Ni)固溶体和Fe₃(P_0.37B_0.63)化合物之外，还包括(Fe, Ni)₃P化合物。     

高压下块状Pd40Ni40P20非晶合金的晶化

 本文研究了Pd₄₀Ni₄₀P₂₀块状非晶在4 GPa及常压下的晶化过程。得到了时间-温度转变图。结果表明：高压下样品的晶化温度明显升高，压力对原子的长程扩散及相分离熔体的粘性流动均有抑制作用。在接近熔点进行高压退火时，获得了单相过饱和固溶体。其晶体结构为面心立方。     

压力对金属玻璃Zr70Cu30晶化温度和激活能的影响

 在0~2 GPa压力范围内，通过测量电阻，研究了压力对金属玻璃Zr₇₀Cu₃₀晶化温度与激活能的影响，并探讨了晶化温度与激活能随压力变化时的相关性。     

高温高压下SrB4O7：Eu2+玻璃的晶化

 利用X射线衍射和Eu²⁺发射光谱方法研究了非晶玻璃SrB₄O₇在高温高压下的晶化。结果表明：在5.0 GPa压力下，200 ℃仍为玻璃态，只有几个强度极低的小峰，表明有晶化的迹象；600 ℃时已基本晶化，但为SrB₄O₇正交相与SrB₄O₇高压立方相二相共存；当温度提高到1 000 ℃时，晶化成了近单相的与常压SrB₄O₇粉末晶体相同的正交结构。伴随晶化度的加强，Eu²⁺发射强度增强，与Ｘ射线衍射结果相一致。     

与Al发生扩散反应的非晶(Fe0.99Mo0.01)78Si9B13晶化

 高压下与Al发生扩散反应的非晶(Fe_0.99Mo_0.01)₇₈Si₉B₁₃（FMSB）的晶化产物与纯FMSB的不同。与Al反应的FMSB非晶在3.0~5.0 GPa、780~900 K热处理时,晶化为α-Fe(Al)和次亚稳非晶合金;在这一压力范围以外,720~900 K热处理时,晶化为α-Fe(Si)、Fe₃B或Fe₂B。与Al发生反应的FMSB非晶可能通过与Al的扩散反应在Al/FMSB界面开始晶化。压力和温度对晶化过程的影响主要是由于α-Fe固溶体的Gibbs自由能随压力、温度和Al含量的变化。     

高压下Zr70Cu30非晶合金的热稳定性和晶化相的变化

 用电阻测量及X射线衍射法研究了非晶Zr₇₀Cu₃₀合金在常压和高压下热稳定性以及晶化相的变化。结果表明压力提高了这种非晶合金的晶化温度并明显地改变了合金中的相平衡关系。在2 GPa压力下，平衡相为Cu₁₀Zr₇和α-Zr的混合物，而常压下为CuZr₂和少量α-Zr的混合物。     

静高压下非晶(Fe0.99,Mo0.01)78Si9B13合金晶化过程的热力学研究

 在600~930 K，常压到7 GPa的范围内，对非晶(Fe_0.99,Mo_0.01)₇₈Si₉B₁₃合金等温等压退火30 min。实验表明：其晶化产物α-Fe(Mo, Si)、Fe₃B和Fe₂B相的析出与所加压力密切相关。压力使非晶(Fe_0.99,Mo_0.01)₇₈Si₉B₁₃合金的晶化温度和亚稳Fe₃B相的析出温度下降，在一定的压力和温度下，亚稳Fe₃B相将向稳定Fe₂B相转变，其转变温度随压力而变化。还对非晶(Fe_0.99,Mo_0.01)₇₈Si₉B₁₃合金的晶化和亚稳Fe₃B到稳定Fe₂B转变的热力学机制进行了讨论，并给出Fe₃B向Fe₂B的相转变方程。     

高压下Al65Co20Mn15合金准晶相得截获及其稳定性的研究

 本文利用高压熔态淬火方法，对Al₆₅Co₂₀Mn₁₅合金进行了研究。首次发现在4.4 GPa压力下淬火的样品中有准晶T相形成。使用电子衍射和X射线衍射对准晶态进行了鉴别。用高温X射线衍射进行了热稳定性研究，发现Al₆₅Co₂₀Mn₁₅合金中准晶T相得晶化温度约为600 ℃。     

平面冲击波高速撞击下Zr41Ti14Cu12.5Ni10Be22.5大块非晶合金的损伤与断裂

 利用二级轻气炮研究了在平面冲击波高速撞击下，Zr₄₁Ti₁₄Cu_12.5Ni₁₀Be_22.5大块非晶合金的损伤与断裂行为。实验结果表明：在高速冲击压缩下，大块非晶合金断裂面的角度小于通常压缩情况的角度，这是由高速撞击下材料极高的应变速率决定的；极高的应变速率变形和局域绝热剪切加热造成局部熔化；在温度和压力的共同作用下，非晶合金发生晶化现象。     

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。     

纳米晶FeCuNbMSiB（M＝Nb，V，Mo）合金的微结构及其电阻率与压力的关系

 X射线衍射和透射电镜的结果表明：非晶FeCuNbMSiB（M＝Nb，V，Mo）合金在540 ℃退火20 min，表面析出的纳米晶是α-FeSi固溶体，粒度为10~20 nm。此外，在0.000 1~2.4 GPa范围内测量了它们的常压室温电阻率以及电阻率随静水压的变化，得到了电阻率与压力的线性关系式。最后探讨了热处理方式和温度对非晶Fe_73.1Cu_1.2Nb_3.2Si_12.5B₁₀合金退火形成纳米晶的影响。     

Crystallinity and dielectric relaxations in semi-crystalline poly(ether ether ketone)

The Maxwell-Wagner-Sillars (MWS) relaxation is studied for semi-crystalline polymers poly (ether ether ketone) (PEEK), in the range 20 Hz-1 MHz and temperature varying from 80 to 330 °C. The parameter is the crystallization condition in the case of PEEK, which is a semi-crystalline polymer considered as a particulate composite. The relaxation found in the semi-crystalline polymers above the α relaxation of the PEEK is ascribed to the trapping of conductive carriers at the interface between crystalline lamellae and the amorphous matrix. The study of PEEK microstructure is based on differential calorimetry and X-rays diffraction. Two lamellae populations have been detected, that depends on the crystallization temperature and its duration. The crystallinity rate is increasing with crystallization temperature and duration. In dielectric studies, the use of the electric modulus instead of permittivity allows us to minimize the ionic conduction and then leads to the appearance of the interfacial relaxation. According to our measurements, the crystallinity rate is not the main factor of the interfacial relaxation intensity, which also depends on the nature and degree of perfection of the lamellae.     

Crystallization process of Bi(Pb)-Sr-Ca-Cu-O glass

A crystallization study has been carried out for rapidly solidified Bi₂Pb_0.5Sr₂Ca₄Cu₅O_x glass. Glass transition temperature T _g, crystallized superconducting phases and microstructural changes were measured and analysed by differential thermal analysis (DTA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The crystallization mechanism of the three superconducting phases — (2201) 20 K phase, (2212) 80 K phase, and (2223) 110 K phase — has been discussed, and a time-temperature-transformation diagram for the glass has been constructed.     

Bi1.8Nd0.2Ti4O11的温致及压致软模相变研究

 采用背用散射的方法，测量了Bi_1.8Nd_0.2Ti₄O₁₁的拉曼光谱。实验结果表明，该掺杂样品发生温致和压致软模相变的温度和压力分别为200 ℃和3.35 GPa。文中讨论了相变点移动的原因及高频声子模随温度和压力的变化。     

(Fe0.1Co0.55Ni0.35)78Si8B14金属玻璃的晶化过程及压力的影响(Ⅰ)——晶化时的相析出过程

用X射线衍射法研究了(Fe_0.1Co_0.55Ni_0.35)₇₈Si₈B₁₄金属玻璃在常压下及20kbar高压下晶化过程中的析出相及析出过程。结果表明在上述压力下晶化过程都分成两个阶段,分别对应于初级晶化和共晶晶化。在常压下,初级晶化时析出fcc-Co晶体,而共晶晶化对应着Ni₃₁Si₁₂和(FeCoNi)₃(SiB)相的析出。随着回火温度的增高或时间的延长,(FeCoNi)₃(SiB)相逐渐转变为(FeCoNi)₂₃B₆相。20kbar高压下的晶化析出过程与常压下不同的是:提高了晶化温度,在共晶晶化阶段出现了Co₂B相。此外,压力还阻止(FeCoNi)₂₃B₆相的形成。从热力学和动力学的角度讨论了压力对金属玻璃晶化过程的影响。 关键词：     

Super-pressed and super-cooled (?) P(EO)20LiBETI

High pressure conductivity measurements have been carried out on P(EO)₂₀LiBETI from 295 K to 368 K. The decrease of electrical conductivity with pressure is larger in the partially crystalline phase (low temperature and low pressure or high temperature and high pressure) than in the fully amorphous phase (high temperature and low pressure). It is found that if the phase transition is approached from the crystalline phase (decreasing pressure), the pressure of the phase transition varies from 0 to 0.23 GPa as the temperature increases from 336 K to 358 K. The shift of the phase transition temperature with pressure is approximately the same as the shift of the glass transition temperature with pressure for pure PEO. This can be understood in terms of the defect diffusion model. If the material is above 336 K and is in the fully amorphous phase, after pressure is increased above the critical pressure, the material remains in the amorphous phase for extended periods of time before transforming to the partially crystalline phase. This is reminiscent of a super-pressed state but may be an indication of slow crystallization kinetics.     

Spherulitic Growth of Poly (Ether Ether Ketone) Crystallized at High Pressure

High-pressure crystallized poly (ether ether ketone) (PEEK) samples were prepared with a piston-cylinder apparatus by varying temperature, pressure, crystallization time, and molecular weight, and were investigated using wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). The applied etching experiments showed that the chemical resistance of the polymer was significantly improved through the high-pressure treatment. The results also revealed that PEEK spherulites with folded-chain lamellae as substructures and with different characteristics were formed at high pressure. Crystalline elliptical micro-spheres consisting of flake-like lamellae with rugged surfaces were observed on the etched samples with SEM, which may diversify niche applications in functional fillers, carriers, adsorbents, etc. Morphological observations suggested that such micro-spheres might possibly have evolved from a novel dendritic crystal. Furthermore, a granular substructure of the lamellae was observed in these single-phase polymer systems with rigid molecular backbones, which further confirmed the model developed by Strobl for polymer crystallization.     

Crystallization Behavior of Amorphous Poly(l-Lactide)

Amorphous poly(l-lactide) (PLLA) was annealed in two different ways: amorphous samples were heated at a given temperature to induce crystallization (one-step annealing); and amorphous samples were first crystallized at a low temperature and subsequently annealed at a higher temperature than the crystallization temperature. Samples thus prepared were measured by DSC. The original amorphous sample exhibited an exothermic peak at about 100°C (exothermic peak I), an exothermic peak just below the melting point (exothermic peak II), and an endothermic peak when it was melted. Exothermic peak I was caused by cold crystallization. When the melting points of PLLA samples, heat-treated in various ways, were plotted as a function of annealing temperature, there was discontinuity at about 120°C. From analyses of wide-angle X-ray diffraction patterns, it was found that when amorphous PLLA was crystallized at a temperature below 120°C, crystallites of the β-form formed, and when annealed at a temperature above 120°C, crystallites of the α-form grew. Thus, exothermic peak I was attributed to cold crystallization of the β-form, and peak II was caused by the phase transition of the β-form to a more stable form.