铸态ZA27合金的压蠕变行为

采用自制的实验装置研究了铸态ZA27合金在常温及高温时的压蠕变行为。在温度为20～160℃和压应力为50～137．5MPa的范围内，随温度和应力的升高，合金的压蠕变量增大，稳态蠕变速率的对数分别与应力和温度的对数曲线有较好的线性关系，稳态蠕变速率符合半经验公式。在不同的温度下，应力指数n相近，平均值为3．87；不同的应力下，表观激活能Qa相差不大，平均值为83．73kJ／mol，材料结构常数A为0．002，稳态蠕变速率由锌的点阵扩散和位错的攀移所控制。     

LA141镁锂合金压蠕变行为的研究

试验研究了铸态LA141合金在温度为30～85℃和压力为37.3～74.6MPa的范围内的压蠕变行为.结果表明,随温度和应力的升高,合金的压蠕变量增大,稳态蠕变速率的对数分别与应力对数和温度呈较好的线性关系,稳态蠕变速率符合半经验公式.在不同的温度下,应力指数n相近,平均值为3.16;不同的应力下,表观激活能Qa相差不大,平均值为104.1 kJ/mol,材料结构常数A为2.68×105,稳态蠕变速率由Li的点阵自扩散和位错的攀移过程所控制.     

Sn-8Zn-3Bi无铅钎料压蠕变行为的研究

试验研究了Sn-8Zn-3Bi无铅钎料在温度为55～100 ℃、压力为9.3～18.6 MPa范围内的压蠕变行为.结果表明,随温度和应力的升高,合金的压蠕变量增大,稳态蠕变速率的对数分别与应力的对数和温度呈线性关系.在试验温度下,应力指数n相近,平均值为3.82;在不同的应力下,表观激活能Qa相差不大,平均值为80.68 kJ/mol.材料结构常数A为6.83×104.压蠕变变形是位错滑移和位错攀移共同作用的结果.     

Mg-Al-RE-Ca-Sr合金的压缩蠕变行为

采用自制的实验装置研究了铸态Mg-4Al-1RE-1Ca-0.2Sr(AECJ411002)合金在温度为125～175 ℃和压力为88～112 MPa范围内的压蠕变行为.结果表明,随温度和应力升高,合金的压蠕变量增大,稳态蠕变速率的对数分别与应力的对数和温度的倒数呈较好的线性关系,稳态蠕变速率符合半经验公式.在不同的温度下,应力指数n相近,平均值为6.19;不同的应力下,表观激活能Qa相差不大,平均值为39.05 kJ/mol,材料的结构常数A为4.18×10-14,稳态蠕变速率由位错攀移控制.AECJ411002合金中沿着晶界分布的Al2Ca相和Al4Sr相具有很高的热稳定性,能提高合金的抗蠕变性能.     

Mg-Al-RE-Ca合金的压缩蠕变行为研究

采用自制实验装置研究了铸态Mg-4Al-IRE-1.2Ca合金在125～175℃、88～112MPa范围内的压蠕变行为.结果表明:随温度和应力升高,合金的压蠕变量增大.稳态蠕变速率符合半经验公式.在不同的温度下,应力指数n相近,平均值为6.24;在不同的应力下,表观激活能Qa相差不大,平均值为37.51 kJ/mol,材料的结构常数为2.88x10-13,稳态蠕变速率由位错攀移控制.合金中沿晶界分布的Al2Ca相具有很高的热稳定性,能提高合金的抗蠕变性能.     

Ti-600合金的高温蠕变行为

研究了Ti-600合金在550～650℃下的高温蠕变行为,实验应力为150～300 MPa.计算了合金在不同应力、不同温度下的稳态蠕变速率、应力指数及蠕变激活能,并在此基础上研究了其蠕变强化机制.蠕变应力为300 MPa时,Ti-600合金的蠕变激活能Q=490.1 kJ/mol;650 ℃,合金的蠕变应力指数n值在6.5～8.5之间变化,表明在实验温度范围内合金的蠕变变形以位错攀移为主,以位错的滑移为辅.     

Sn-0．7Cu无铅钎料的压入蠕变行为研究

采用自制的蠕变装置研究Sn-0.7Cu合金钎料在温度为60～120 ℃,压力为30～50 MPa下的压入蠕变性能,并利用SEM和XRD对合金蠕变前后组织的变化进行分析.结果表明,随温度和应力的增加,合金的蠕变速率增大,稳态蠕变速率符合半经验公式,并得出了该合金的本构方程.通过对其蠕变后应力指数、蠕变激活能及显微组织变化的分析,压入蠕变变形机制主要由位错攀移引起.     

快速凝固/粉末冶金Mg-6wt％Zn-5wt％Ca合金的压缩蠕变行为研究

采用雾化-双辊急冷法和热挤压工艺,制备了快速凝固/粉末冶金Mg-6wt％Zn-5wt％Ca合金,研究了合金在150～200℃和压力为30～70MPa的压缩蠕变行为.结果表明,随温度和应力的升高,合金的压蠕变量增大,稳态蠕变速率的对数分别与应力的对数和温度的倒数呈线性关系,稳态蠕变速率符合半经验公式;在175℃时,应力指数n为2.27;在70MPa条件下,表观激活能Qa为133 kJ/mol;合金的压蠕变速率由镁的自扩散和位错滑移控制.     

砂型及金属型铸造ZA27合金的压蠕变行为

采用自制的试验装置研究了ZA27合金在砂型和金属型铸造条件下的压蠕变行为。结果表明，合金第一阶段的压蠕变量和稳态蠕变速率随着温度和应力的增高而增大，在较低温度时，金属型铸造合金第一阶段的蠕变量低于砂型铸造合金的。合金的压蠕变符合经验公式ln(t/s)=C-nln(σ/MPa) Q/(RT)，砂型铸造合金的应力指数n和蠕变激活能Q分别为3.88和85.44kJ/mol，而金属型铸造合金的应力指数和蠕变激活能分别为3.49和81.02kJ/mol，合金的压蠕变由锌的点阵自扩散和位错的攀移控制，在整个试验温度和应力范围内，砂型铸造合金的压蠕变抗力高于金属型铸造合金的。     

锆对ZA27合金压蠕变行为的影响

采用自制的压蠕变试验装置研究了锆对ZA2 7合金压蠕变行为的影响。结果表明 ,在试验温度 2 0℃～ 1 60℃和压应力 50MPa～ 1 37 5MPa范围内 ,ZA2 7 Zr和ZA2 7合金压蠕变第一阶段的变形量和稳态蠕变速率随着温度和应力的增高而增大 ,但在 1 0 0℃以下时 ,ZA2 7 Zr合金第一阶段的蠕变量及稳态蠕变速率低于ZA2 7合金 ,合金的压蠕变抗力高于ZA2 7合金 ,在 1 60℃则相反。合金的压蠕变行为可用等式 :lnt=C -nlnσ +Q RT表达 ,其中 ,材料结构常数C不同导致两种合金的蠕变行为不同。ZA2 7 Zr合金的应力指数n和蠕变激活能Q分别为 3 63和 87 32kJ·mol-1 ,ZA2 7合金的应力指数和蠕变激活能分别为 3 46和 81 0 9kJ·mol-1 。表明Zr的加入并不影响ZA2 7合金的蠕变机制 ,均由锌的点阵自扩散和位错的攀移控制     

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.     

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.     

Structural Optimization of Electromagnetic Swirling Flow in Nozzle of Slab Continuous Casting

During the slab continuous casting process, the flow field of molten steel in the mold plays a decisive role in the quality of the slab. In this paper, electromagnetic swirling flow in nozzle technology is proposed to control the flow field in mold.This technology can drive molten steel to rotate inside the submerged entry nozzle by electromagnetic force, thereby controlling the flow field. This research shows that it can reduce the impact of molten steel on the bottom of nozzle and partly reduce the negative pressure at the upper part of nozzle outlet which is even eliminated by optimizing the structure and angle of nozzle. The area of heat flux of the mold wall becomes larger, and the crest value of heat flux gets lower than that without swirling in nozzle and any nozzle optimization. The meniscus fluctuates smoothly, and the flow velocity at the top surface is within a reasonable range. The temperature field distribution in the mold is uniform which was beneficial to the growth of equiaxed crystal and decreased element segregation.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).