铋粒子相在大变形过程中对晶粒细化的影响（英文）

通过背散射电子衍射(EBSD)研究Al-8Zn和Al-6Bi-8Zn两种合金经5道次室温等径角挤压(ECAP)过程中的组织演变和晶粒细化行为。经过5道次等径角挤压,两种合金都形成了超细晶粒。然而,Al-6Bi-8Zn合金的晶粒明显小于Al-8Zn合金,这说明在等径角挤压过程中铋粒子对晶粒细化有明显的作用。通过测定等径角挤压后两种合金的硬度发现,经5道次等径角挤压之后,Al-6Bi-8Zn合金的硬度高于Al-8Zn合金。此外,讨论了铋粒子在等径角挤压过程中对变形行为及最终合金强度的影响。     

ECAP对碳纳米管/AZ31复合材料显微组织的影响

采用碳纳米管孕育块铸造法制备了碳纳米管/AZ31镁基复合材料,并对其进行了等径角挤压实验.利用光学金相显微镜对它的显微组织进行了观察和分析,研究了等径角挤压变形工艺对复合材料显微组织的影响规律.结果表明:等径角挤压工艺可明显细化复合材料的晶粒组织;随着变形道次的增加,复合材料平均晶粒尺寸不断得到细化,组织更加均匀.     

ECAP对粉末冶金ZK60镁合金组织和性能的影响

采用粉末冶金法制备了ZK60镁合金,对挤压态镁合金在不同温度和道次下进行了ECAP处理,研究了不同温度和道次对材料微观组织和性能的影响。结果表明,较高温度条件下能够实现镁合金棒材的等径角挤压,且在挤压温度为260℃时,材料的抗拉强度和伸长率达到最佳值。进一步在此温度下进行不同道次的等径角挤压后发现,合金的晶粒尺寸明显细化,材料的性能进一步得到改善,抗拉强度和伸长率分别达到341.5 MPa和29.3%。研究表明,合适的等径角挤压温度和不同的道次能够改善粉末冶金法制备的镁合金的力学性能。     

ECAP法制备超细晶铜的再结晶行为研究

在室温下，采用ECAP技术对纯铜进行了1-10道次的挤压，使其组织大大细化，得到了均匀、细小的等轴晶，平均晶粒尺寸为0．75μm。通过对不同ECAP道次后的退火试样的硬度测量和观察组织，结果表明：随ECAP道次的增加．开始再结晶的温度降低，再结晶软化的速率增加，ECAP8道次试样在433K发生静态再结晶。     

采用双通道等径侧面挤压法提高AA5083铝合金力学性能（英文）

采用双通道等径侧面挤压剧烈塑性变形工艺提高AA5083铝合金的力学性能。采用多组实验研究路径类型(A和B路径)和挤压道次对材料力学性能的影响。挤压道次为6道次,挤压温度范围为573~473 K,采用金相、硬度测试和拉伸测试研究这些工艺参数的影响。硬度测试表明经6道次挤压后,硬度提高了64%,且分布均匀。屈服强度和抗拉强度分别提高了107%和46%。这是由于晶粒的剧烈剪切变形和变形温度降低导致的晶粒细化。TEM结果表明,经DECLE 6道次变形后,合金的平均晶粒尺寸从退火态的100μm减小至200 nm。对比研究了路径A和B的实验结果,并得到一些重要结论。     

挤压温度对往复挤压工业纯镁组织性能的影响

研究了工业纯镁的往复挤压工艺,在不同温度下用往复挤压工艺细化工业纯镁晶粒.挤压4道次,用金相显微镜观测了不同挤压温度条件下晶粒细化效果,测试了晶粒细化后的强度和硬度.结果表明,在相同挤压道次下,随着挤压温度的提高,晶粒度不断增大,拉伸强度和伸长率下降；在150℃往复挤压后,拉伸强度达到221 MPa,伸长率为23％.     

等通道转角挤压镁合金的微观组织和力学性能

采用自制的90°模具,分析不同的ECAP挤压路径对AZ31镁合金变形后的微观组织和力学性能的影响;对挤压后的试样进行显微组织观察、硬度测试,研究等通道挤压工艺(ECAP)对AZ31镁合金的晶粒细化效果.结果表明:Bc路径晶粒细化效果较好,随着挤压道次增加,晶粒发生细化,7道次后晶粒尺寸由原来的70μm细化到4.8μm左右;硬度值随道次增加显著提高,3道次后达到最大值90.81MPa,之后随道次增加,硬度略有下降,趋于稳定.     

等径角挤压制备CuCrZr合金的抗软化性能

研究了CuCrZr合金等径角挤压(ECAP)后的微观组织演变及软化温度.结果表明,固溶态CuCrZr合金经路线B_c(每挤一道次后试样沿同一方向旋转90°)等径角挤压10道次后组织细化至亚微米级,超细晶晶粒较为等轴、均匀.等径角挤压10道次后合金的软化温度约为530℃,但550℃时,合金的硬度仍高达161HV,这说明ECAP后合金的抗软化能力并没有降低.因为ECAP促进了时效时析出相的析出,使得析出相更为弥散、细小,从而提高了合金的力学性能.     

等径角挤压晶粒细化技术对纯铝显微组织演变、力学性能和腐蚀行为的影响(英文)

在室温下,采用等径角挤压法加工纯铝样品10道次。研究等径角挤压道次数对加工样品显微组织演变、力学性能、变形均匀性和腐蚀行为的影响。所施加的应变导致晶粒尺寸明显减小,等径角挤压前,晶粒尺寸为390μm,经等径角挤压2、4和10道次后,晶粒尺寸分别减小至1.8、0.4和0.3μm。随着等径角挤压道次数的增加,显微硬度、变形均匀性和拉伸强度增大,而伸长率下降。浸泡试验、开路电势、Tafel极化、循环极化和恒电位测试表明,与铸态样品相比,在3.5%Na Cl溶液中,经等径角挤压样品的耐蚀性明显提高。增加挤压道次数能成功用来生产具有高错位角、高力学性能和耐蚀性的超细晶大块纯铝。     

前处理工艺对Al-Zn-Mg-Cu合金ECAP的影响

研究了退火、固溶、双级时效以及回归（RRA）热处理4种前处理工艺对Al-Zn-Mg-Cu系铝合金多道次等径通道挤压（ECAP）变形过程的影响。试验结果表明,退火态试样在常温下只能进行2道次ECAP变形,而其余3种状态常温下经1次ECAP变形后便发生严重的开裂现象。退火处理后的试样采用523K温度加热可进行多次ECAP变形,挤压后晶粒明显细化且逐渐向等轴状演化。8道次之后晶粒细化趋于缓和,10道次后等效真应变达到了6．2,晶粒为0．8μm左右的等轴状。随着挤压道次的增加,试样显微硬度不断增大,且存在定量关系。     

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).