熔盐中电解钛铁矿制备TiFe合金

通过在CaCl2熔盐中电解钛铁矿制备TiFe合金,研究了熔盐电解钛铁矿的反应过程,分析了电解产物的成分及电解效率。结果显示,钛铁矿的还原经历了优先生成Fe到逐步形成TiFe2、TiFe的合金化历程,中间产物包括 CaTiO3、Fe2TiO4、TiO。反应最先生成的合金是TiFe2合金,通过Ti和TiFe2的互扩散最终转变成TiFe合金, 说明扩散是反应的控制步骤。相同电解条件下,钛铁矿较混合氧化物难电解。这是由于钛铁矿颗粒较大,其杂质是固溶到钛酸铁中的,脱氧更难,电解效率较低     

熔盐电解脱氧制备TiV合金

在CaCl_2熔盐中电解混合氧化物合成TiV合金.电解电压为3.0～3.2 V,电解温度为900 ℃,钛、钒混合氧化物作为阴极,石墨棒作为阳极.初步研究了电解原理.结果显示,反应过程是混合氧化物逐步还原生成组分可控的TiV合金.还原经历了从优先生成钛到逐步形成TiV合金的合金化历程.中间产物包括CaTiO_3、钒和钛的低价氧化物.     

熔盐电脱氧法制备ZrMn2储氢合金

采用熔盐电脱氧法,由MnO2和ZrO2混合氧化物直接合成ZrMn2合金。研究烧结温度、电解电压及电解时间等工艺参数对产物组成的影响。在900°C的CaCl2熔盐中,经900°C烧结的混合氧化物阴极在3.1 V恒电压下电解12 h,可制备出纯相的ZrMn2合金。XRD和循环伏安结果表明,在电解过程中,Mn-O化合物首先还原成单质Mn,ZrO2和CaZrO3再在单质Mn表面还原,并与其合金化,形成ZrMn2合金。以粉末微电极为工作电极,循环伏安测试结果表明,所制备的ZrMn2合金表现出良好的电化学储氢性能。     

含钛高炉渣直接提取Ti5Si3及杂质去除机理

采用固体透氧膜可控氧流冶金技术,利用含钛高炉渣成功提取出Ti5Si3合金粉末。SEM、XRD和EDX分析表明:含钛高炉渣中Ca、Mg、Al等金属杂质得以有效去除,获得的Ti5Si3相具有与直接电解钛硅混合氧化物(摩尔比TiO2:SiO2=5:3)产物相似的微观形貌及物相组成。同时对熔盐电解过程的杂质去除机理进行了分析。     

氧化物与氟化物的加入对氯化物熔盐体系电解制备Mg-La合金的影响

以石墨坩埚为阳极,钨棒为阴极,在750℃的MgCl2-LaCl3-KCl熔盐体系中,采用恒电位电解制备Mg—La合金。研究氧化物和氟化物的加入对电解的影响,通过XRD对部分Mg-La合金产物和电解渣进行表征。随着MgO或La203在熔盐电解质中加入量的增加,电流效率和所得合金产物的质量都减小,表明MgO和La203参与电解质中的反应。在加入的氧化物质量相同的情况下,MgO与La2O3相比对电流效率和合金产物质量的影响更明显。XRD研究结果表明：MgO或La2O3加入到熔盐电解质中后,有LaOCl生成,LaOCl电解渣的生成是氧化物对电解消极影响的主要原因。在本实验的的熔盐体系中,CaF2的加入对消除MgO的负面影响没有积极意义,这可能和镧化合物在熔盐电解质中的复杂反应有关。     

熔盐电解制备低成本Ti12LC钛合金的研究

采用熔盐电解法由混合氧化物成功制备出了低成本Ti12LC合金,并对脱氧过程机理进行分析。结果显示:脱氧反应过程首先生成CaTiO3、低价氧化物Ti6O、Ti2O和Ca2Al2O5;其次随脱氧时间的进行钛的低价氧化物含量逐步增加,再其次出现金属钼,最后生成Ti12LC合金相。由于MoO2的理论电压低于TiO2、Al2O3,因此钼优先还原,且钼在-Ti中能固溶,所以最终钼是以固溶体形式存在于钛中,而Fe2O3虽然理论分解电位更低,但由于含量低,而没有检测到铁的单质还原。通过对电解产物表面的背散射电子像分析,发现电解制备出的产物其形貌和Ti12LC合金的组织相似。     

熔盐电脱氧法制备CoSn合金

在850℃的CaCl2熔盐中,以烧结后的Co3O4-SnO2片体为阴极,高纯石墨棒为阳极,采用恒电压电解,制备CoSn合金,研究烧结温度、电解时间对电解过程的影响。采用电子扫描显微镜(SEM)和X射线衍射仪(XRD)分析样品的微观形貌和电解产物的相组成,并采用循环伏安法研究其反应机理。结果表明:经850℃烧结的混合氧化物试样,在2.1V工作电压下电解12h,可制备出海绵状纯相的CoSn合金。在电脱氧过程中,单质Co首先分步还原,锡的氧化物与熔盐反应后在单质Co表面还原,形成CoSn合金。     

温度对钛精矿熔盐电解制备钛铁合金的影响

在CaCl2 熔盐中,以钛精矿为阴极,电解制备了钛铁合金,并对产物进行了XRD和SEM检测。对比不同温度下电解产物的结果表明,温度对扩散合金化过程影响显著,不同温度下电解产物的物相和结构有明显不同。850 ℃下电解的最终产物是颗粒大小为1 μm的TiFe2和Ti离散球型结构,而900 ℃下电解的最终产物是颗粒大小为3 μm的TiFe空间网状结构     

直接电解金属氧化物制备CeCo_5合金

在CaCl2熔盐中,以Co3O4和CeO2混合氧化物为原料,采用熔盐电脱氧法制备CeCo5合金。研究电解电压、烧结温度等对电脱氧过程的影响。采用SEM和XRD对不同条件下制备的产物微观形貌和相组成进行表征,并结合动电位极化法,研究电脱氧机理。采用循环伏安法研究材料的电化学性能。结果表明：随着电解电压的升高和烧结温度的降低,电脱氧速度逐渐加快。在850°C下烧结的混合氧化物试样,在3.1V电压下电解,可制备出纯相的CeCo5合金。在电脱氧过程中,Co3O4还原成单质Co,CeO2还原成CeOCl,CeOCl在单质Co表面还原而形成CeCo5合金。所制备的合金表现出良好的电化学循环稳定性。     

Mn和V对TiAl合金热腐蚀的影响

Mn和V对TiAl金属间化合物在900℃(Na，K)2SO4熔盐中热腐蚀行为的影响有所不同．TiAl合金中加入Mn后，最外层的腐蚀产物为以Al2O3为主、另有少量TiO2的混合物；内层是Al，Ti和Mn的混合氧化物以及Ti的硫化物．加Mn在一定程度上减弱了TiAl合金的耐蚀性TiAl和TiAl-Mn合金中加入V后耐蚀性明显变差，最外层腐蚀产物以TiO2为主，并含有少量Al2O3和微量的V2O5，腐蚀层中的V2O5引起Al2O3的酸性溶解，因而不能形成保护性的Al2O3层，形成的TiO2和Al2O3混合膜的黏附性差，较易剥落。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.