双金属复合带材轧制过程有限元模拟

采用刚塑性有限元法,以实验结果为依据,以大型有限元软件ANSYS为分析工具,对双金属复合带材轧制过程进行计算机数值模拟,分析了双金属复合带材同步或异步轧制过程中,轧辊和轧件的应力,应变分布和轧件的塑性流动变形情况以及轧制力和力矩,以动画的方式模拟轧制过程,给出了一种预测轧制结构,减少实验时间和费用的有效方法。     

汽车散热器用4045/363/353铝合金复合带材退火工艺研究

为了提高汽车散热器用铝合金复合带材的强度和改善散热器在工作温度下的稳定性,在工业生产条件下研制出4045/363/353新型铝合金复合带材.主要研究了不同的成品退火温度对该复合带材组织和力学性能的影响,确定了0.25 mm厚度4045/363/353铝合金复合带材的成品退火工艺制度为420℃(9+1)h.该复合带材的抗拉强度为171.5 N/mm2,伸长率为17.4%,强度比原来的434、LQ2-1铝合金复合带材的提高40 N/mm2～50 N/mm2,主要是由于芯材363铝合金的合金化元素含量比原来3003铝合金芯材高一些的结果.     

退火温度对异步轧制铜/铝复合带材组织与性能的影响

采用异步轧制工艺进行了铜/铝薄带的复合,并对复合带材进行了退火处理。利用金相显微镜、扫描电镜和拉伸试验机进行了复合带组织的观察和性能的测定。结果表明,复合带材的退火温度与其剥离强度呈抛物线关系,复合带材剥离强度在300℃保温1 h达到最大值。退火温度升高,促进界面元素扩散,界面化合物层变厚,伸长率增加,但温度过高会导致界面开裂。     

西北有色金属研究院的主要研究领域(之三)——超导材料

本院是国内最早从事超导材料研究的单位之一,有数十名高、中级工程技术人员和专业人员,主要开展实用超导材料和高Tc、Hc的超导材料以及超导磁体、低温测试技术等方面的研究,取得了多项成果。例如,NbTi单芯线,高铜比复合带,多芯NbTi/Cu-CuNi届缆带,     

铝合金双铸造组织坯料对钎焊复合带材性能的影响

研究了铝合金双铸造组织坯料对钎焊复合带材包覆率均匀性、Si原子的扩散情况及抗下垂性能的影响。结果表明:与热轧组织包覆层制备的复合带材相比,铸造组织包覆层制备的复合带材包覆率较均匀,Si原子从包覆层向芯层的扩散程度明显降低,表现出良好的抗下垂性能。     

Si元素扩散对4343/3003/7072铝合金复合带性能的影响

采用抗下垂试验,利用金相显微镜、SEM、拉伸试验机、游标卡尺等研究了Si元素扩散对4343/3003/7072铝合金复合带性能的影响。结果表明:经抗下垂试验后,Si元素沿着芯材晶界向芯材扩散,同时,芯材发生熔蚀,并在晶界处形成新的Al-Si共晶。Si元素扩散越深,复合带的力学性能越小;芯材的晶粒越大,Si元素扩散程度越小,复合带的抗下垂性能就越好。     

冷轧铜-铝复合带翘曲变形研究

铜-铝复合带是将铜带复合在铝带上随后冷轧而成,但冷轧过程中复合带会发生翘曲。借助于MSC. MARC有限元软件建立了冷轧铜-铝复合带的二维模型,研究了道次压下率、铜带与铝带的厚度比和轧制速率对冷轧铜-铝复合带翘曲程度的影响。采用二辊冷轧机进行了铜-铝复合带的冷轧试验,并与有限元模拟结果进行了对比。结果表明:采用厚度比为1∶4的铜带和铝带,以175 mm/s的速率冷轧的铜-铝复合带,随着道次压下率从55%增大至70%,其曲率先减小后增大,以57.5%的道次压下率冷轧的复合带平直度最好。以60%的道次压下率和175 mm/s的速率冷轧的复合带,其曲率随着铜带与铝带厚度比的增加而减小。采用厚度比为1∶6的铜带和铝带,以70%的道次压下率和125～225 mm/s的速率冷轧的复合带,其曲率先减小后增大,以180 mm/s的速率冷轧的复合带平直度最好。     

嵌入式铝/钢冷轧复合带材铝层的厚度波动形成机理与控制（英文）

研究压下率和铝带初始厚度对冷轧复合嵌入式铝/钢复合带材铝层厚度波动的影响,分析铝层厚度波动的形成机理,提出改善复合带材铝层厚度均匀性的措施。结果表明,随着压下率的增加,铝层厚度波动逐渐增大。当压下率低于40%时,初始铝带厚度对复合带材铝层厚度波动量的影响较小;当压下率高于40%时,随初始铝带厚度的减小,复合带材的厚度波动量增大。表面处理形成的钢带表面硬化层引起钢带表层变形和钢/铝界面结合程度不均匀是导致复合带材铝层厚度波动的主要原因。采用合适的钢带表面处理方式降低钢带表面硬化程度,改善钢带表层变形和钢/铝界面结合程度的均匀性,可有效降低铝/钢复合带材的铝层厚度波动。     

冷弯成型有限元模拟技术的研究进展及发展趋势

对塑性成型有限元理论的研究和冷弯成型单元技术的发展进行归纳总结,并对冷弯成型有限元模拟的发展趋势和有限元模拟的优势、存在的问题进行了分析。     

464—H14铝合金复合带材抗下垂性能的影响

研究了汽车全铝水箱用464-H14铝合金复合带材成品轧制前软化退火温度，以及成品轧制时冷加工率对材料抗下垂性能的影响。结果表明：退火温度越高，材料抗下垂性能越差，冷加工率控制在20%～40%时，材料具有好的抗下垂性能，为了提高材料的抗下垂性能，必须控制和减少复合带皮材里的Si原子向芯材的扩散。     

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).