医用多孔Ti-10Mo合金的制备及力学性能

以元素粉末为原料添加造孔剂碳酸氢铵,采用粉末冶金模压烧结技术制备了多孔Ti-10Mo合金,探讨了烧结工艺与造孔剂含量对合金组织、孔隙特征和力学性能的影响规律。结果表明,在1300℃烧结可制备出具有典型魏氏体组织、孔隙分布均匀的多孔Ti-10Mo合金材料;随着造孔剂含量增加,合金孔隙率增加,孔径变大孔壁变薄,当造孔剂含量达到50%,孔隙结构互相贯通,孔径尺寸大幅增加;添加50%~60%造孔剂,制备Ti-10Mo合金孔隙率为62.8%~66.9%,平均孔径尺寸为485.6~545.9μm,其弹性模量为2.9~1.3 GPa,抗压屈服强度为129.2~56.1 MPa。     

微孔无机分离膜用多孔陶瓷支撑体的研制

以碳化硅为原料，通过调整骨料粒径等级，并添加造孔剂和粘结剂，制备了孔隙率在35％-45％，平均孔径为40～60μm，具有狭窄的孔径分布（PSD）和很高强度的用于无机分离膜的微米级多孔陶瓷材料。在一定的烧成温度下，多孔陶瓷的平均气孔孔径与平均骨料粒径成正比。随着保温时间的延长，气孔孔径趋向均一；平均孔径增大，PSD变窄。增加粘结剂用量有利于促进PSD的集中趋势。多孔陶瓷的强度取决于骨料颗粒间的颈部连接强度，并随粘结剂用量的增加和烧成温度的提高而上升。     

先驱体作粘结剂低温制备SiC多孔陶瓷

分别以聚碳硅烷和硅树脂作粘结剂，SiC微粉作骨料，在惰性气氛中1000℃下低温制备出SiC多孔陶瓷。所得样品的气孔率在43％～52％之间，抗断裂强度最高达到了18．59MPa，而且样品的孔径呈单峰分布。分析比较了由这2种不同粘结剂制备的SiC多孔陶瓷性能。     

用聚硅氧烷和羟甲基纤维素制备泡沫陶瓷

选用聚硅氧烷为主要原料,用羟甲基纤维素为造孔剂,制备了SiOC泡沫陶瓷。研究了造孔剂含量、成型压力、裂解温度对泡沫陶瓷抗压强度及孔隙率的影响,并对泡沫陶瓷的微观形貌进行了分析。结果表明,随着造孔剂含量的增加,泡沫陶瓷的孔隙率随之增大,而抗压强度则随之降低;在40MPa～120MPa的成型压力范围内,随着成型压力的增加,泡沫陶瓷的孔隙率逐渐降低,而抗压强度不断增加;在10001400℃温度范围内,随着裂解温度的升高,泡沫陶瓷的抗压强度先增加后降低,而孔隙率不断降低;当羟甲基纤维素的含量为50％、成型压力为80MPa、裂解温度为1250℃时,所制备的泡沫陶瓷的抗压强度为43MPa,孔隙率为51％。微观结构分析显示,SiOC泡沫陶瓷微孔分布均匀,以三维交错的网状孔道相互贯穿。     

造孔剂添加量对凝胶注模成型工艺制备8YSZ多孔陶瓷性能的影响

采用叔丁醇基凝胶注模成型工艺结合添加造孔剂法制备了高固相含量的YSZ多孔陶瓷。研究了固相含量为50%(体积分数)时,不同造孔剂添加量对烧结8YSZ多孔陶瓷的孔径及其分布、气孔率、抗弯强度以及热导率的影响。研究结果显示:8YSZ多孔陶瓷的气孔分布均匀,孔径在10μm左右,孔壁致密;气孔率在22.9%～39.8%之间,且随着造孔剂添加量的增加而增加;抗弯强度随着造孔剂添加量的增加而减小,最高可达(85.24±2.31)MPa;热导率在0.735～1.108W/m·K之间,且随着造孔剂添加量的增加而降低。上述结果表明,凝胶注模工艺中同时添加造孔剂不仅可以实现高固相含量多孔陶瓷的制备,而且可以同时实现孔结构可控,最终得到兼具有高强度、高气孔率和低热导率的8YSZ多孔陶瓷。     

凝胶辅助发泡法制备三维互联多孔SiC陶瓷

通过机械搅拌发泡结合冷冻-凝胶法制备了三维互联多孔SiC陶瓷材料,所获得的多孔陶瓷材料孔径分布均匀、孔结构可调并具有双级孔结构。研究了PVA含量与搅拌速度对多孔陶瓷孔结构及性能的影响。结果表明,随着PVA含量的增加,孔结构均匀程度和联通性提高、一级孔孔径尺寸逐渐减小且孔壁变薄。当ω(PVA)/ω(SiC)质量比为1.5时,样品孔径分布最均匀;并且随着搅拌速度的增大,孔隙率增加、联通性增强、一级孔孔径尺寸减小。当转速为1600 r/min时,SiC多孔陶瓷的孔隙率和抗压强度分别为88.42%和4.36 MPa。     

多孔NiTi形状记忆合金的制备工艺

以NH_4HCO_3为造孔剂,利用元素粉末混合烧结法制备了多孔NiTi形状记忆合金。研究了压制压力、烧结温度和烧结时间对多孔NiTi合金孔结构的影响,并分析了其物相组成。结果表明:随压制压力的增加,平均孔径和孔隙率逐渐减小;随烧结温度提高,多孔NiTi合金的平均孔径减小、孔隙率先增加后减少,孔隙分布趋于均匀;随烧结时间延长,多孔NiTi合金的平均孔径及孔隙率先增加后减少。在造孔剂添加量50%,压制压力250 MPa,烧结温度1000℃,烧结时间6 h条件下可制备出孔结构均匀(平均孔径为314μm,孔隙率56.3%)的多孔NiTi合金,其基体相为B2(NiTi)相。     

不同无机铵盐对陶瓷结合剂CBN砂轮造孔的应用研究

分别研究了无机铵盐NH4F、NH4Cl、（NH4）2SO4和NH4HCO3的不同添加量对低温陶瓷结合剂CBN砂轮造孔的影响,采用气孔率、抗折强度以及试样SEM断口形貌对造孔效果进行了评价。结果表明：NH4Cl使砂轮开裂,不能作为低温陶瓷结合剂CBN造孔剂。NH4F造孔效果不明显,不适合造孔。（NH4）2SO4造孔剂的质量分数应控制在5％以内,质量分数达到5％时,砂轮孔隙率为36．14％,抗折强度为29．03MPa,气孔皆为小孔,气孔可调性差。NH。HCO,造孔剂质量分数应控制在15％以内,质量分数为5％时,砂轮孔隙率为34．19％,抗折强度为40．32MPa;质量分数增加到15％时,孔隙率达到42．5％,抗折强度为29．16MPa,且大孔径气孔比例随质量分数的提高而提高,气孔可调性好。     

纳米SiC填料对SiOC泡沫陶瓷性能的影响

以聚硅氧烷为先驱体,采用先驱体转化法及有机泡沫浸渍法相结合制备了SiOC泡沫陶瓷。研究了纳米SiC填料含量对SiOC泡沫陶瓷的抗压强度、孔隙率的影响,并对泡沫陶瓷的微观形貌进行了分析。结果表明：随着纳米SiC填料含量的增加,Si0C泡沫陶瓷抗压强度先升高后降低;在相同的裂解温度下,添加纳米SiC填料可提高泡沫陶瓷的孔隙率。当SiC填料含量达5％时泡沫陶瓷抗压强度达最大值17．8MPa,其孔隙率为88％。微观结构分析显示,SiOC泡沫陶瓷呈三维网状结构,孔径为100～500μm,具有良好的贯通性,且孔筋处结构较为均匀致密。     

造孔剂含量对多孔BN/Si3N4复合陶瓷结构和性能的影响

以Si3N4为基体、BN为添加剂,采用添加PMMA造孔剂法制备出具有优良力学性能和介电性能的多孔BN/Si3N4复合陶瓷。通过对材料的物相组成、显微结构、气孔率、孔径分布、力学及介电性能的表征和测试,系统分析了造孔剂含量对材料结构和性能的影响。结果表明:随着造孔剂含量的增加,多孔BN/Si3N4复合陶瓷的气孔率增大,抗弯强度减小,介电常数减小,而介电损耗呈微弱的上升趋势。当造孔剂粒径为2μm,含量为5%(质量分数,下同)时,制备出气孔率达到40.8%,抗弯强度达到(114.67±10.73)MPa,介电常数为4.0,介电损耗为3.3×10-3的高性能多孔BN/Si3N4复合陶瓷透波材料。     

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.