热处理对Fe_(81)Ga_(19)合金组织结构与磁致伸缩性能的影响(英文)

采用电弧熔炼法制备了Fe81Ga19合金多晶样品,研究了不同热处理工艺对合金组织结构及磁致伸缩性能的影响。样品经过700℃、800℃和900℃保温后采用空冷、炉冷和淬火3种冷却方式。结果显示,经过不同热处理后样品的微观组织均为单相bcc结构,而磁致应变从34×10-6到94×10-6不等;当热处理温度为800℃时,淬火处理后可获得较好的磁致伸缩性能(88×10-6),而热处理温度较高(900℃)时,采用炉冷的方式可获得较好的磁致伸缩性能(94×10-6)。推测热处理方式和晶体取向对Fe81Ga19合金磁致伸缩性能有较重要的影响

Low-temperature Preparation of Anatase TiO_2 Powders by Hydrothermal Method

[中文文摘]以钛酸四丁酯为前驱体,采用热液法在低于100℃的条件下制备了纳米晶TiO2粉体。运用DSC、XRD和HRTEM对所获得的TiO2粉体进行表征。XRD结果表明:所得到的TiO2粉体都是锐钛矿相,颗粒大小随着热液处理温度(60～100℃)的升高而增大,由Scherrer公式计算,其粒径介于4.8～6.9nm。同时,研究了所获TiO2粉体在紫外光下降解亚甲基蓝的性质。[英文摘要]Nanocrystalline TiO2 in the anatase phase has been obtained by hydrothermal method with tetrabutyl titanate below 100 ℃. The synthesized powders were characterized by differential scanning calorimetry (DSC), X-ray diffraction (XRD), and high resolution transmission electron microscope (HRTEM). XRD results show that the synthesized powders are all anatase. The grain size of the powders increases with the increment of the hydrothermal temperature from 60 degrees to 100 degrees, calculated grain size is from 4.8 to 6.9 nm by Scherrer method. The samples were investigated for the photodegradation properties of methylene blue (MB) solutions exposed to UV light illumination

Martensitic transformation, ductility, and shape-memory effect of polycrystalline Ni56Mn25-xFexGa19 alloys

Buttons of high-temperature shape-memory alloy Ni56Mn25-xFexGa19 were prepared by arc melting under argon atmosphere. The specimens were hot rolled to 1 mm. plates, and their martensitic transformation behaviors, ductilities, and shape-memory effects were investigated through differential scanning calorimetry and bending tests. It was found that the brittleness of polycrystalline Ni2MnGa was ameliorated through introduction of a ductile phase by Fe addition. Ni56Mn17Fe8Ga19 alloy shows great potential as a practical high-temperature shape-memory alloy with martensitc transformation start temperature above 200 degrees C. It can bear strain of 6 % before fracture in bending tests and shows a maximum reversible strain of 3.5 %

Effect of Trace Boron on Microstructure and Mechanical Properties of Ti-9V-3Al-3Cr-3Zr-35Mo Alloy

Conference Name:2nd International Conference on Manufacturing Science and Engineering. Conference Address: Guilin, PEOPLES R CHINA. Time:APR 09-11, 2011.The effects of trace boron on microstructure and mechanical properties of beta type Ti-9V-3Al-3Cr-3Zr-3.5Mo (wt. %) alloy have been investigated in this study. Upon the addition of 0.02 wt. % boron, the grain size of the B-modified alloy was almost four times smaller than that of the B-free alloy. Accordingly, the tensile strength and elongation of B-modified alloy increased from 712 MPa and 14.6 % to 813 MPa and 17.9 %, respectively, mainly due to the effect of grain refinement

50味中药及其复方与抗生素对河流弧菌的体外抑菌作用

用牛津杯法选择大黄、黄柏、黄连等50种单味中药进行河流弧菌、金黄色葡萄球菌体外抑菌试验,并以抗菌活性较好的药物组成二联、三联复方,药物质量浓度分别为60和240 mg·mL-1,进行中药复方抗菌活性研究,同时用抗生素进行河流弧菌药敏试验。目的是筛选出对河流弧菌敏感的中草药、抗生素及其复方。结果表明,黄连、诃子等单方对河流弧菌抑菌作用明显,为极敏感;在60 mg·mL-1低药物浓度时,黄柏、黄连组成的复方对河流弧菌抑菌作用为极敏感;在240 mg·mL-1药物浓度时,黄柏、黄连等组成的9个复方中药对河流弧菌抑菌作用属极敏感,黄连、板蓝根、黄柏等4个复方中药对河流弧菌的抑菌作用明显,为极敏感。河流弧菌对恩诺沙星、盐酸多西环素、氟苯尼考、土霉素及甲氧苄啶/磺胺甲噁唑5种药物高度敏感。部分中药对河流弧菌抑制作用不明显,黄连、板蓝根、黄柏等4个三联复方中药药效最强。可组成多种三联复方中药或中西药联用复方,均有良好的抑制作用。2018年开放课题基金项目(LYC2018RS04,闽海鸥[2018]31号)福建省自然基金项目(2016J01167,2018J01455)国家自然科学基金(31702384,31502194)福建省科技重大专项(2016NZ0001-3)2017年集美大学研究生教育教学改革研究项目(集大研No.[2017]18号)教育部鳗鱼工程研究中心开放基金项目(RE201704

铁磁性Co-Fe 记忆合金的马氏体相变特性及形状记忆效应

Microstructure, martensitic transformation temperature and shape memory effect of Co-Fe alloys were investigated by optical observation, X-ray diffraction, DSC and bending tests. Results show that the shape memory effect of Co-Fe alloys is associated with the fcc/hcp martensitic transformation. When Fe content is higher than 5.65wt%, the microstructure exhibits single gamma phase with fcc structure. When Fe content is lower than 5.6wt%, the microstructure consists of gamma phase and epsilon martensitic phase with hcp structure. The martensitic transformation temperatures of Co-xFe alloys are almost linearly decreased with increasing Fe content, following the relationship: M(s) (degrees C) = 417-69.97x(Fe%). The highest recoverable strain of Co-4Fe (wt%) alloy is 0.86%. It is believed that Co-Fe alloys will exhibit better shape memory effect after proper heat treatment and shape memory training

Thermodynamic calculation of phase equilibria in Cu-Ni-Sn ternary system

[中文文摘]基于Cu-Ni-Sn三元系的相平衡和热力学的实验信息,采用亚正规溶体模型描述液相和fcc相的Gibbs自由能,为了预测该体系中bcc相的A2 B2有序无序转变,bcc相的Gibbs自由能采用双亚点阵模型进行描述。利用CALPHAD(相图计算)方法评估了Cu-Ni-Sn三元系各相的热力学参数,计算的富Cu侧相图和热力学性质与实验数据比较一致。并对该三元系中bcc相的A2 B2有序无序转变及fcc相的溶解度间隙进行了计算。这些计算结果对利用析出强化以及Spinodal分解开发高强度和高导电性的新型Cu基合金的组织设计具有一定的指导意义。[英文文摘]On basis of the phase equilibria and thermodynamic properties of the Cu-Ni-Sn ternary system by experiment,the thermodynamic assessment of the Cu-Ni-Sn ternary system was carried out by the CALPHAD(calculation of phase diagrams) method.The Gibbs free energies of liquid and fcc phases were described by the subregular solution model,and Gibbs free energies of the bcc phase were described by the sublattice model in order to predict the order-disorder phase transition in the bcc phase.A set of parameters parameters describing the Gibbs energies of different phases in this system were optimized by experimental data. The calculated result s agree well the experimental data. The A2/B2 ordering temperature and miscibility gap of the fcc phase can be predicted. These calculated result s provide an effective guide for microst ructure design of the new type Cu base practical materials with high strength and high electric conductivity.国家杰出青年科学基金资助项目(50425101); 教育部科学技术研究重点资助项目(105100)

中国式学科评估:问题与出路

今年四月份,教育部学位与研究生教育发展中心(以下简称"教育部学位中心")邀请全国学位授予单位参加全国第四轮一级学科整体水平评估。随之,各个高校展开了一场大规模、高级别的学科评估申报及材料提交总动员。第四轮学科评估自发布起也引发了学界的广泛关注和热烈讨论。高等教育是中国崛起的思想发动机,关涉民族复兴的未来,而学科评估是近年来中国高等教育学科建设成就的集中展示,其意义和影响可谓深远。为了更好推进学科评估科学进行,特别是促进高等教育健康发展,《探索与争鸣》编辑部邀请全国

A repetitive thermomechanical process to produce nano-crystalline in a metastable austenitic steel

Nano-crystalline grains of about 100 nm were obtained in a metastable austenitic steel by a repetitive thermomechanical process consisting of conventional cold rolling and annealing. The nano-grained austenite was transformed on annealing from the strain-induced martensite, which had formed during cold rolling. The nano-structured austenitic steel exhibits not only high strength (above 1 GPa) but also good elongation (above 30%). (c) 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved