低镍电热合金高温热变形组织分析

本文利用热模拟技术对铁基低镍电热合金的热变形行为进行了试验研究,绘制出了该合金的高温变形真应力—真应变曲线,并结合热变形后的显微组织着重分析了铝元素对该合金热变形行为的影响

局部热载荷诱导热障涂层界面分层断裂问题

以激光辐照对热障涂层面层进行局部加热,模拟超燃冲压发动机燃烧室热障涂层服役的高热流、高温度梯度载荷环境,研究热障涂层的可能破坏模式.首先给出了YAG激光局部加热试验方法、过程和界面破坏的典型形貌;然后,基于理论分析与有限元模型化研究,计算了表面局部受热时热障涂层体系的温度场、变形场和应力场,分析了热障涂层破坏的力学机制.研究结果表明,在这种局部迅速加热的载荷条件下,热障涂层将由于陶瓷层-粘接层的界面分层断裂而失效.参数化模型研究发现热障涂层体系的关键结构参量、性能匹配对界面分层断裂驱动力具有显著影响且存在优化区间

表层弥散预应变硬化对薄钢板变形局部化的影响

试验研究了具有一定形貌及粗糙度的激光毛面薄钢板及同材质普通薄钢板的失稳行为。结果表明激光毛面薄钢板变形局部化过程明显滞后于普通板，其表层弥散分布的预应变硬化点在稳定薄板变形、延缓变形局部化过程中起到重要作用

激光和电子束表面强化技术的发展及其应用

激光和电子束表面强化是当前引入注目的两种高新技术。文章系统地介绍了这两种技术的发展状况及应用，同时比较了二者的优缺点。最后对目前存在的问题及未来的发展方向作了简要的讨论

钢中贝氏体长大方式的TEM研究

利用TEM考察了钢中贝氏体铁素体/奥氏体相界面台阶结构及奥氏体精细结构。根据实验结果提出了贝氏体二次层错切变模型及组织形貌示意图

Synthesis and antimicrobial activity of mono-benzyl fumarate

以顺丁烯二酸酐和苯甲醇为原料,经过单酯化和异构化两步得到反丁烯二酸单苄酯,并考察异构温度、异构时间、异构剂用量对产率的影响.结果表明反丁烯二酸单苄酯最佳工艺条件为:顺丁烯二酸酐:苯甲醇为1.1∶1(摩尔比)、反应温度为90℃、时间为20 MIn、异构温度为90℃、异构时间为2 H、异构剂无水三氯化铝为0.7 g(顺丁烯二酸酐9.2 WT%),产率为65.5%.fT/Ir和nMr表征结果表明,反丁烯二酸单苄酯的结构与理论预测一致;生物学活性实验证实该化合物对细菌、真菌具有显著的抑菌杀菌作用,有望开发成为新型抑菌剂.The mono-benzyl fumarate was synthesized by two-step: esterification and isomerization.The results showed that the optimum conditions for mono-benzyl fumarate were:molar ratio of maleic anhydride to benzyl alcohol 1.1∶1,reaction temperature 90 ℃,reaction time 20 minutes and then isomerized in the presence of 0.7 g aluminum chloride anhydrous for 2 h at 90 ℃ with the yield of 65.5%.FT/IR and NMR showed that all the characterization data were consistent with the expected compositions and structures.Antimicrobial activity against bacteria,fungus were studied,The result showed that mono-benzyl fumarate had strong antibacterial activity and could be used as antimicrobial sterilization.福建省自然科学基金计划资助项目(2006J0262);厦门市科技项目(3502Z20073027

Uniaxial tensile and cross-sectional indentation tests to investigate the adhesion between the brittle Cr coating and the ductile steel substrate

Adhesion of a coating on its substrate is a crucial parameter determining performance and reliability of coating-substrate system. In this work, the uniaxial tensile and cross-sectional indentation tests are used to investigate the adhesion between the brittle Cr coating and the ductile steel substrate. The uniaxial tensile test results show the maximum shear flow stress level of the ductile steel substrate can only serve as a lower bound estimate on the ultimate shear strength of the interface. The cross-sectional indentation test results show the interfacial decohesion does not occur prior to the cracking of the brittle Cr coating

A hydride-induced-reduction strategy for fabricating palladium-based core-shell bimetallic nanocrystals

Zheng, NF (通讯作者)One key challenge in making high-quality bimetallic nanocrystals is to prevent self-nucleation of individual metal components. We report in this work an effective seeded growth strategy that uses activated hydrogen atoms as the reducing agent to prepare core-shell bimetallic nanocrystals. In the developed method, Pd nanocrystals serve as the seed and catalyst as well to activate H-2 for the reductive deposition of Ag. The unique feature of the developed method is that the activated hydrogen atoms are confined on the surface of the Pd seeds. Consequently, the self-nucleation of Ag is effectively inhibited so that the deposition of Ag occurs only on Pd. The mechanism studies reveal that reductive growth of Ag on Pd seeds proceeds until the Pd surface is fully covered by Ag. The Ag/Pd ratio in the prepared Pd@Ag nanocrystals is readily fine-tuned by the amount of AgNO3 or H-2. The method is effective for depositing Ag on Pd nanocrystal seeds with different morphologies such as nanosheets, nanocubes, tetrahedra and nanowires. More importantly, the deposition of Ag on Pd nanowires allows preparation of flexible transparent electrode material with sheet electronic conductivity of 271 S sq(-1) at a transmittance of over 90%.MOST of China 2011CB932403 2014CB932004 NSFC of China 21131005 2133300

激光熔凝和熔敷在热轧辊强化中的应用

为提高热轧辊寿命对球墨铸铁、白口铸铁热轧辊进行了激光熔凝、熔敷实验研究,并对激光处理效果进行了现场轧制实时寿命评估.研究确认:球墨铸铁、白口铸铁激光熔凝小样的硬度随扫描速度的降低和激光功率的增大而提高.分别按轧钢量、磨损量计算,球墨铸铁、白口铸铁激光熔凝热轧辊寿命分别比原来延长50%和15.6%～23.4%.利用激光熔敷技术在白口铸铁热轧辊上可以成功制备无宏观裂纹、气孔和夹杂存在的镍基合金涂层.现场轧制后表面也无宏观缺陷存在,寿命延长18.7%～37.4%