Thermophysical properties of a Ti–44%Al–8%Nb–1%B alloy in the solid and molten states

The families of titanium aluminide intermetallic alloys have attractive high temperature mechanical properties which make them potential candidate materials for a wide range of applications, particularly in the aeronautic and automobile sectors. The development of appropriate manufacturing techniques is an essential stage in the engineering exploitation of these materials, e.g., Induction Skull Melting is one of the techniques which needs to be optimised for the casting of titanium aluminides. Research is underway to develop a computer model of this process but data are required for the key thermophysical properties. Pulse-heating techniques have been used to measure properties for the Ti–44Al–8Nb–1B system. Rectangular samples have been prepared and are resistively heated as part of a fast capacitor discharge circuit. Time-resolved measurements with sub-μs resolution of currents through the specimen were made with a Pearson probe current monitor using the induction principle. Voltages across the specimen were determined with knife-edge contacts and voltage dividers, and radiance temperatures of the sample were measured with a pyrometer. These measurements allow the calculation of specific heat and dependencies between enthalpy, electrical resistivity and temperature of the alloy up into the liquid phase. Data for thermal diffusivity have been obtained by using the Wiedeman–Franz relation. The results are compared with those obtained using DSC and the four-probe method to measure the temperature dependence of the resistivity.     

Effect of Al in Ti－microalloyed Mn－Ni－Mo welding wire on microstructure and toughness of deposited metal

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TiCp/Al预制块在Mg中熔化过程研究

将TiCp／Al预制块以不同的工艺加入到Mg液中进行熔化试验。结果表明，未搅拌时TiCp／Al预制块在800℃的Mg液中保温60min后仍不熔化，采用合适的搅拌工艺可使TiCp／Al预制块熔化，并且使TiC粒子在熔体中均匀分布。TiCp／Al预制块在Mg液中的熔化过程机理为：基体Al通过熔化和对淹扩散进入到Mg液中，TiC粒子间的结合力需通过搅拌产生的剪切力才能破坏，并随Mg液流动进入到Mg液中，机械搅拌可使TiC粒子Mg液中均匀分布。     

电场固溶对2091A1-Li合金显微结构的影响

用电子探针及透射电镜研究了２０９１ＡｌＬｉ合金的电场固溶对显微结构的影响。结果发现，电场固溶通过促进含铜相溶解提高铜元素的固溶程度，加剧Ｌｉ原子在晶界上的非平衡偏聚，导致析出相δ′分布不均匀，体积分数减少，晶界上出现粗大的δ平衡相，Ｔ１及Ｓ′相均匀弥散分布，合金的力学性能（Ｔ６）达到了应变时效处理（Ｔ８）的水平。     

ZL114铝合金激光--龟弧的复合焊接

设计了一种激光-电弧复合热源焊接ZL114合金的新工艺，并对焊后的试件进行了X光检测、抗拉强度和全相组织等实验。结果表明，该种新工艺对铝合全有良好的适应性和可行性，是焊接领域的一个趋势。     

Electrochemical corrosion behavior of 2A02 Al alloy under an accelerated simulation marine atmospheric environment

The corrosion behavior of 2A02 Al alloy under simulated marine atmospheric environment has been studied using mass-gain, scanning electron microscope/energy dispersive spectroscopy (SEM/EDS), laser scanning confocal microscopy, X-ray diffraction spectroscopy and localized electrochemical methods. The results demonstrate that the relationship between the corrosion induced mass-gain and the corrosion time is in accordance with the power rule. The mass-gain increases gradually during the corrosion time, while the corrosion rate decreases. With ongoing of the corrosion, corrosion products film changed from a porous to a compact structure. The various spectroscopic data show that the corrosion products films composed mainly of Al(OH)₃, Al₂O₃ and AlCl₃. The electrochemical corrosion behavior of the 2A02 Al alloy was studied by electrochemical impedance spectroscopy (EIS).     

花形氧化锌纳米粒子的制备及其光催化性能

以氯化锌和氢氧化钠为原料,水为反应介质,密闭加热的条件下制备了花形ZnO纳米粒子。借助扫描电镜及X射线粉末衍射仪等仪器,对产物的形貌、结构进行了表征;对产物的生长机理做了研究,同时研究了反应条件对产物的影响,另外对产物进行了光催化测试。结果表明,花形骨架在反应初期就已经产生,反应时间增加,花形粒子变大;改变氯化锌和氢氧化钠的物质的量比,产物形貌产生了较大变化,分别生成了另一种形貌的花形粒子和片状粒子;通过光催化测试表明,所得的产物均有良好的光催化性能。