Electrical Resistance Measurement of Glass Transition and Crystallization Characteristics of Zr—Al—Cu—Ni Metallic Glasses

In this paper,glass transition and thermal stability of the Zr-Al-Cu-Ni metallic glasses were investigated by using electrical resistance measurement(ERM),DSC and X-ray diffraction techniques.The experimental results show that the ERM is capable of detecting the glass transition of the amorphous alloys and can help to distinguish the crystallization products of the Zr-Al-Cu-Ni metallic glasses owing to the difference of the electrical resistivity between the precipitation phases.     

Microstructural transformations of heat affected zones in duplex steel welded joints

The influence of the welding thermal conditions exemplified by heat input and heat treatment after welding on the structure of the heat affected zone (HAZ) UNS S31803 has been analysed. The post weld treatment was used to create the precisely defined thermal conditions for the decomposition of primary phases in the HAZ, by a multi-layer welding thermal cycle stimulation. Detailed analyses of the microstructure and chemical composition of the phases in the different post welded conditions were performed by scanning electron microscopy (SEM) combined with energy dispersive spectrometry (EDS) and transmission electron microscopy (TEM). Three types of secondary precipitates have been observed: secondary austenite (γ₂), carbides: M₂₃C₆ and M₇C₃. The dependence of the secondary austenite volume fraction and morphology in the HAZ on thermal cycle have been interpreted. The eutectoid decomposition of the primary phases in the analysed thermal conditions was confirmed.     

The Problem of Estimating the Uncertainty of the Fixed Point Temperature Due to the Presence of Impurities

The main problems in estimating the uncertainty due to the presence of impurities in the material: the absence in the documents of a unique definition of the quantity being measured – the fixed point temperature, the lack of agreed methods of realizing the fixed points and the insufficient justification of the equations used for the estimate, are analyzed. The results of a measurement of the melting point of gallium are presented, which differ in the conditions in which they were realized – with one and two liquid-solid interfaces and different solidification conditions, are presented. The reasons for the considerable difference between the values of the temperatures obtained in these experiments are discussed.     

用扫描电镜研究硅酸盐、硼酸盐和磷酸盐玻璃的表面

本文采用扫描电镜及能谱仪分别研究了硅酸盐、硼酸盐和磷酸盐玻璃的风化、离子注入和离子交换，观察了表面形貌、离子交换的深度分布及离子注入对表面析晶的影响。     

Upconversion emission of a novel glass ceramic containing Er: BaYF5 nano-crystals

In order to develop highly efficient upconversion (UC) material, Er³⁺-doped oxyfluoride glass ceramics containing BaYF₅ nano-crystals were fabricated for the first time. The randomly distributed BaYF₅ nano-particles with the size of nearly 25 nm precipitated from the glass matrix at about 700 °C, then tended to aggregate slightly with the increase of heating temperature, resulting in the enhancement of Er³⁺ UC emission in the wavelength ranging from 500 nm to 700 nm. The UC process was found very sensitive to Er³⁺ content: with the increase of Er³⁺ content from 0.5% to 1.0%, the UC intensity behaved with drastic exaltation; while further increasing Er³⁺ content to 2.0% resulted in a notable fluorescence quenching. Significantly, the UC efficiency of present glass ceramic preponderates notably over that of the previously reported glass ceramic containing LaF₃, implying its superior UC potentiality.     

Bruchanalyse an Hohlgläsern

Failure analysis of hollow glasses The failure analysis is very important to clarify damages of hollow glasses. Damages of glass bottle through over pressure are very often linked with damages to persons. This is the reason why the causal research is from particular importance. Different surface characteristics of glass fragments as well as the fracture pattern give hints to the direction of the crack, the stress just before breakage and the reason of stress. A reconstruction of the bottle is a further helpful instrument for cause studies. The difference of the various characteristics of the surface will be explained. Further on there will be discussed different reasons and mechanism of fracture.     

Influence of Drying Conditions on Ascorbic Acid during Convective Drying of Whole Persimmons

Degradation kinetics of food constituents may be related to the matrix molecular mobility by glass transition temperature. Our objective was to test this approach to describe ascorbic acid degradation during drying of persimmons in an automatically controlled tray dryer with temperatures (40 to 70°C) and air velocities (0.8 to 2.0 m/s) varying according a second order central composite design. The Williams-Landel-Ferry model was satisfactorily adjusted to degradation curves for both control strategies adopted—constant air temperature and temperature fixed inside the fruit. Degradation rates were higher at higher drying temperatures, independent of the necessary time to attain the desired moisture content.     

玻纤增强石油发酵尼龙的热稳定性研究

利用热重动力学方法研究了玻纤增强ＰＦ尼龙（即石油发酵尼龙）的热稳定性能。玻纤和偶联剂均对ＰＦ尼龙具有热稳定化作用，且硅烷Ａ１１００对ＰＦ尼龙的热稳定化作用最为显著。     

Dielectric behaviour of glasses and glass ceramics in the system BaO-PbO-TiO2-B2O3-SiO2

Glasses with varying molar ratios of PbO/BaO in the system BaO-PbO-TiO₂-B₂O₃-SiO₂ were prepared keeping (BaO + PbO)/TiO₂ ratio equal to one. The glasses were ceramized by two-stage heat treatment. X-ray diffraction indicates that PbTiO₃ crystallizes in lead-rich glasses while BaTiO₃ precipitates in barium-rich compositions. Solid solution (Ba, Pb)TiO₃ does not seem to crystallize over the entire range of compositions. Simultaneous presence of PbO and BaO in the initial glass composition reduces the yield of ferroelectric phase. Dielectric properties have been interpreted in terms of microstructural features.     

Al-4%Cu过饱和合金在强磁场中时效行为

采用差示扫描量热仪分析并结合显微硬度测试、电子探针分析、透射电镜观察研究了10-T稳恒强磁场对Al-4％Cu（质量分数）合金130℃时效过程中各沉淀相析出行为的影响。结果表明：在低温时效初期强磁场的引入加速了铜的扩散，降低了G.P.（Ⅰ）区的溶解激活能，促进其溶解，各沉淀相的析出与溶解温度均向低温处移动，时效进程加快；另外，强磁场时效后沉淀相尺寸减小；施加强磁场试样的硬度明显高于未施加磁场试样的，时效硬化效果加强。