原位增强相(TiB2+Al3Ti)形成的热力学分析

采用混合盐法制备了(TiB2 Al3Ti)/Al-4.5Cu原位复合材料,对增强相的形成热力学进行了分析,并采用差热分析法(DTA)对混合盐反应体系的热量变化进行分析.结果表明,Al-Ti-B三元体系中,TiB2的形成能力最强.但因[Ti]实际相对过剩,与Al结合形成Al3Ti,最终制得的复合材料中增强相为TiB2和Al3Ti;差热分析表明了混合盐体系加入到Al-4.5Cu熔体中,可以发生原位反应,形成增强相.原位反应的开始温度为900 ℃,结束温度为1 032 ℃.     

混杂增强相(Al3Ti-TiB2-SiC)的形成热力学分析

对利用原位反应与高剪切液态搅拌复合专利技术制备的Al3Ti-TiB2-SiC/Al-13%Si复合材料的增强相的形成热力学进行了理论计算和分析,并采用差热分析法(DTA)进行了试验验证.研究表明:(1)Al-Ti-B体系加入到Al-13%Si熔体中可发生原位反应,形成增强相,原位反应的开始温度为905.3℃,结束温度为1 061.23℃;(2)Al-Ti-B体系加入到Al-13%Si熔体中,制备颗粒增强Al-13%Si复合材料的增强相为TiB2和Al3Ti,但TiB2形成能力最强.     

反应热压（A12O3＋TiB2＋A13Ti）／Al复合材料的组织形成机制

采用B或B2O3、TiO2和Al粉反应热压制备了原位(Al2O3 TiB2 Al3Ti)／Al复合材料，采用光学显徽镜、扫描电镜和透射电镜分析了原位复合材料的显微组织。热压状态下，反应生成相Al3Ti呈大块不规则形状，尺寸约几十微米；Al2O3和TiB2为细小弥散质点，TEM分析发现TiB2颗粒呈六边形，而Al2O3颗粒呈等轴状。在以Al粉、TiO2粉和B粉为原料制备的复合材料中，除反应生成了大块的Al3Ti相外，还有细小针状Al3Ti相沉淀析出，且呈弥散分布。热挤压后大块的Al3Ti被破碎成细小弥散质点。Al2O3在TiO2和B2O3粉末表面生成；TiB2在B或B2O3粉表面形成，因而均呈弥散分布，且尺寸细小。自TiO2中还原出的Ti溶入液态Al中形成A13Ti时，Ti可在液态Al中长距离扩散，因而Al3Ti呈大块不规则状。     

放电等离子合成Ti3AlC2-TiB2复合材料的相形成研究

采用放电等离子烧结工艺,以Ti,Al,B4C,TiC为原料制备Ti3AlC2／TiB2复合材料。通过X射线衍射分析了从600℃到1300℃Ti3AlC2／TiB2系统反应过程的相形成规律。用扫描电镜观察了不同温度下试样的显微组织演变。结果表明,在900℃之前,主要的反应是Ti和Al反应生成Ti—Al金属间化合物,900℃之后,Ti—Al金属间化合物与TiC逐渐生成Ti3AlC2和TiB2相,形成致密Ti3AlC2／TiB2复合材料。     

原位反应合成TiB2的生长行为

研究了(K2TiF6 KBF4)/A356混合盐反应体系中原位合成TiB2增强相的热力学行为及其晶体生长行为.结果表明,原位反应温度明显影响反应体系最终产物及TiB2增强相的形貌.(K2TiF6 KBF4)/A356体系原位反应温度应控制在850 ℃为宜,由此可以完全消除TiAl3脆性相,并生成六棱粒状TiB2增强相颗粒,提高增强相强化效果.     

AlTi5B1对亚共晶铝硅合金的组织和性能的影响

研究了AlTi5B1的加入量对亚共晶铝硅合金微观组织和力学性能的影响.结果表明:A1Ti5B1的加入量对合金的抗拉强度影响较大,并在Ti含量为0.06％时,抗拉强度达到最大值；对伸长率的影响和对抗拉强度的影响是一致的；对合金的硬度影响较小.加入AlTi5B1细化处理后,TiB2粒子和三元相Ti(Al1-x,Six)3数量增加,是α-Al相的有效形核核心,起主要的细化作用；第二相(Fe相,AlCu相)的形貌及分布发生了变化,强化了晶界,减弱了Fe相的有害作用.     

热压烧结反应生成TiB／Ti-4．0Fe-7．3Mo复合材料的组织与性能

采用机械合金化(MA)的方法将B和FeMo粉末与金属Ti的粉末混合均匀，球磨10h后，真空热压烧结制备原位生成TiB增强Ti-4．0Fe-7．3Mo复合材料。在金相显微镜(OM)下观察，复合材料由TiB增强区与不含TiB的基体所组成。TEM研究表明：增强区足由反应生成的TiB增强的α和β-Ti2相共同组成，在α和β-Ti相交界处分布的TiB不仅尺寸较人，而且数量也较两相内部的TiB多。在α钛中观察到少量的平行于α相板条的特殊TiB的存在。反应生成的TiB呈截面为六边形的针状，与基体的界面清洁、平直匹配良好。复合材料的三点弯曲强度和杨氏模量均随反应生成TiB体积含量的增加而降低。     

放电等离子原位烧结制备TiC＋TiB／Ti复合材料

采用放电等离子烧结（SPS），通过Ti与B4C之间的原位反应合成TiC＋TiB／Ti复合材料。首先通过热力学计算判断可能发生的反应，利用x射线衍射（XRD）、扫描电镜（SEM）对球磨混合粉以及烧结后材料的相组成和显微组织进行了研究，测定材料的相对密度和硬度，并探讨了Ti与B4C采用放电等离子烧结制备TiC＋TiB／Ti复合材料的致密化过程和反应机理。结果表明，采用SPS技术，在1150℃保温5min的条件下，Ti与B4C能同步完成反应、烧结、致密化，生成TiC＋TiB／Ti复合材料，并且原位生成的增强相分布均匀且细小。     

Ti6Al4V表面激光熔覆NiCrBSi+B4C涂层的组织结构

选用NiCrBSi及2％民C混粉在Ti6Al4V合金表面进行激光熔覆处理，使基体中的Ti和B4C发生化学反应原位生成TiC、TiB2硬质增强相，制备出TiC与TiB2等增强相增强钛基复合材料涂层。综合运用XRD、SEM、EPMA和TEM等分析手段研究了优化熔覆工艺条件下的NiCrBSi＋B4C激光熔覆层的组织结构与相组成，并对复合涂层进行了硬度测试，结果表明：NiCrBSi＋2％B4C熔覆层的微观组织是在γ—Ni和Ni3Ti＋Ni3B共晶的基体上均匀分布着TiB2、TiC、CrB等相的多元组织，激光熔覆层的硬度比Ti6Al4V基体硬度提高到3～4倍。     

原位TiB2(p)/Fe复合材料的制备及其显微组织

利用Fe—Ti5—B熔体反应制备了TiB2颗粒增强铁基复合材料，研究了该材料的显微组织。热力学分析表明，Fe-Ti-B熔体具有反应生成TiB2的可能性。试验结果表明，TiB2颗粒均匀分布于α—Fe晶粒中，晶内TiB2粒子平均间距大于晶界。TiB2粒子尺寸大多为1-6μm，形状大多为接近等轴的多面体。     

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.     

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.     

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.     

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。     

A STUDY OF TEMPERATURE-DEPENDENT VALENCE BOND STRUCTURE OF TITANIUM

On the basis of energy and shape method for the determination of the valence bond (VB) structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is e_c~(2.9907) · (s_c~(0.4980) d_c~(2.4927)) ef1.0093 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.