基于LOM原型快速制造电火花加工电极的研究

利用LOM原型，把化学镀、电铸和电弧喷涂技术结合起来快速制造电火花加工电极，是实现模具快速制造的有效途径。本文分析了LOM原化学镀工艺的关键问题，通过反复试验，解决了LOM纸质原型的导电化问题，并经过脉冲电铸铜及以电弧喷涂紫铜作背衬，得到了适用于电火花成形加工的电铸铜电极。该工艺方法尤其适合于生产中、小型零件的模具的快速制造。     

基于RP原型的电弧喷涂快速模具制造技术研究

基于RP原型的电弧喷涂快速模具制造工艺是一项模具制造新技术。本文介绍了这种工艺的原理和方法。并重点讨论了该制模技术的关键。     

面向对象的板料成形过程模具集成化设计思想

根据板料成形过程 ,并利用目前的一些先进制造工艺和技术 ,结合CAD/CAM和仿真软件 ,提出一个面向对象的、板料成形过程模具集成化设计系统。介绍了系统的组成部分、功能及实现过程。     

面向对象的板料成形过程集成化设计思想

根据板料成形过程,并利用目前的一些先进制造工艺和技术,结合CAD／CAM和仿真软件,提出一个面向对象的、板料成形过程模具集成化设计系统。介绍了系统的组成部分、功能及实现过程。     

基于电弧喷涂和电刷镀的快速制模技术

提出了1种电弧喷涂和电刷镀一体化的快速制模技术 ,该技术采用电弧喷涂工艺在母模表面快速沉积一层致密的低熔点金属薄壳 ,从而制作出模具的型腔 ,然后采用电刷镀工艺在模具工作表面刷镀强化涂层 ,以显著提高模具表面的硬度和耐磨性。并介绍了电弧喷涂和电刷镀一体化快速模具制造设备 ,所述快速模具制造方法和设备用于汽车新车型开发和样车试制 ,可以显著降低开发成本、缩短试制周期     

基于LOM原型的电弧喷涂模具制造工艺

论述了基于LOM原型电孤喷涂快速模具制造的基本原理及流程,并详细地介绍了LOM原型制造中的电弧喷涂金属丝的选择方法.     

汽车大型覆盖件的数字化成形技术

本文介绍金属板料数字化成形的方法 ,这是一种用CAD模型直接驱动 ,实现设计与制造一体化的柔性快速成形方法。其采用快速原型制造技术的“分层制造”思想 ,将复杂的三维形状分解成一系列二维层上的数据。并根据工件的几何形状信息 ,用三轴数控设备控制一个成形工具头作三维曲线运动 ,逐层对板料进行塑性加工 ,使板料逐步成形为所需的汽车覆盖件     

快速原型与铸造技术的集成成形制造

在介绍快速原型技术的基础上,提出了快速原型与铸造相集成的快速零件／模具制造工艺,可以实现零件／模具的快速精确成形制造。通过案例分析了快速原型技术在铸造中的应用,认为该技术在铸造行业中具有广泛地应用前景。     

渐进成形技术在滚塑模具制造上的应用

应用渐进成形技术,采用交叉分割材料法,提升材料成形特性,避免了板料在成形过程中被拉裂的现象,实现快速精准地滚塑模具制作;采用模具结构简化法,将复杂滚塑模具结构分解为若干简单几何体,便于板料渐进成形;成功解决了手工制作滚塑模具的弊端。试验结果表明:采用渐进成形技术制作给排水管道检查井滚塑模具的方法适用有效,该工艺的制造成本低、周期短、精度高,对板料渐进成形技术在滚塑模具中广泛应用具有一定的应用价值。     

应用电弧喷涂技术制造塑料模具

应用电弧喷涂技术制造塑料加工用模具(电弧喷涂制模)是电弧喷涂应用的一个新领域,是一种低成本、高效率的制造模具方法。本文综述了电弧喷涂制模技术国内外的发展状况,并根据我们对此项技术的研究结果,介绍了电弧喷涂制模技术中,脱模剂的选择,浇注填充材料的选择,制模工艺等。     

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.     

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。     

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.     

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.     

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.