等通道转角挤压7075铝合金动态再结晶组织晶粒度预报

采用等通道转角挤压(ECAP)对7075铝合金试样进行挤压,利用有限元软件对ECAP的连续动态再结晶组织晶粒度进行预报,采用有限元和实验相结合的方法,研究不同挤压道次对7075铝合金A路径ECAP过程组织晶粒度的影响。模拟结果表明,经过一道次、二道次和四道次A路径ECAP后试样中心区域的晶粒尺寸分别为24.8μm、20.2μm、16.7μm,晶粒随着挤压道次的增加不断细化。通过金相定量法计算可得一道次、二道次和四道次A路径ECAP实验后试样中心区域的晶粒度分别为26μm、20μm、16μm,与有限元预报结果吻合良好,最大误差小于5%,证明基于连续动态再结晶模型的有限元预报准确性较高。     

工业纯钛ECAP温变形的力学性能及热稳定性

采用两通道夹角φ=90°,外圆角ψ=20°的模具,成功实现了工业纯钛BC方式6道次ECAP温变形,累积等效真应变达到约6.3,制得ECAP温变形试样后,对各道次ECAP温变形后的工业纯钛进行压下量为55％的冷轧变形.同时,观察分析了变形试样的显微组织及性能,并对各道次ECAP温变形试样的热稳定性进行研究.结果表明,经过6道次ECAP变形后,工业纯钛的抗拉强度达到760MPa,伸长率为40％.当退火温度低于400℃时,ECAP变形试样的组织变化不大,显微硬度下降缓慢;当退火温度高于400℃时,由于发生了再结晶,显微硬度显著下降.     

等通道挤压镁合金工艺的研究

采用等通道挤压(ECAP)对AZ91镁合金在预热温度为350、400、450、500 ℃下进行了2、4、6、8、10道次的挤压.采用光学显微镜和透射电子显微镜分析了试样经过不同的变形工艺的显微组织变化.结果表明,随着挤压道次和变形温度的增加,ECAP变形后的试样表面形态愈加平滑光洁,晶粒可细化到几微米,在透射电镜下观察ECAP后的显微组织,晶粒内部出现高密度位错,产生位错塞积.第二相粒子阻碍位错运动,从而促进动态再结晶,对细化晶粒起着重要作用.     

等通道挤压后镁合金的微观结构研究

对Mg-6Zn-IGd-0．6Zr合金在预热温度为350、400、450℃下进行了2、4、6道次的挤压。采用光学显锻镜和透射电子显微镜分析了试样ECAP变形前后的显微组织变化，采用显维硬度计对Mg-6Zn-1Gd-0．6Zr合金ECAP变形前后进行了硬度测试，采用X-射线分析法分析了ECAP变形过程中晶面的转动。结果表明：ECAP不仅能够将晶粒细化到纳米级，而且能够提高材料的硬度；Mg-6Zn-IGd-0．6Zr合金ECAP变形后晶粒内部出现高密度位错．促进动态再结晶，对细化晶粒起着重要的作用。     

等通道挤压镁合金的微观组织与硬度

对ZK60镁合金进行了C方式(相邻道次间旋转180°)等通道角挤压.采用光学显微镜、扫描电子显微镜和透射电子显微镜分析了试样ECAP变形前后的显微组织变化;采用显维维氏硬度计进行了硬度测试,并分析了ECAP变形对材料硬度的影响规律.结果表明:在ECAP挤压后的组织中有高密度的位错,它促成再结晶并晶粒细化到1～3μm;在经过6道次挤压后,合金的硬度达到76.3 HV.     

挤压道次对航空用工业纯铝ECAP组织和性能的影响

采用等通道转角挤压(ECAP)方法加工航空用工业纯铝以形成细晶结构,对其组织、力学性能以及腐蚀性能进行了测试,研究挤压道次对工业纯铝组织和性能的影响。结果表明:ECAP加工后工业纯铝试样基体晶粒变长并细化。随挤压道次(7道次前)增加,其拉伸强度与表面硬度上升,伸长率降低。经过ECAP加工后,试样腐蚀电位提高,点蚀电位正移,耐蚀性能得到改善。工业纯铝试样ECAP后表面属于点蚀类型,并随挤压道次增加,腐蚀区的数量逐渐降低。     

Mg-1Zn-1Gd合金在等径角挤压下的晶粒细化机理及织构演变

研究等径角挤压(ECAP)对Mg-1Zn-1GD合金组织、织构和动态再结晶行为的影响,结果表明,在350℃等径角挤压后,试样的显微组织由细小的再结晶晶粒组成,基体中有大量均匀分布的等轴晶。8道次获得平均晶粒尺寸为3.6m的均匀超细晶粒结构。不连续动态再结晶(DDRX)和连续动态再结晶(CDRX)导致晶粒细化。利用电子背散射衍射技术对织构进行了分析。结果表明,经过4次ECAP后,形成了较强的基础纹理(多重随机分布~19.76)。随着挤压道次的增加,挤压合金板材基面上的晶粒主要沿挤压方向拉长,取向分布由集中状态向分散状态转变。织构减弱,最大值为15.66。最后表明织构与Mg-1Zn-1GD合金的平面各向异性有关.     

等径弯曲通道变形制备超细晶铜的热稳定性

室温下采用等径弯曲通道变形(Equal Channel Angular Pressing,ECAP)C方式进行了纯铜(99.95%)12道次挤压变形。通过等温和等时退火,研究ECAP变形后铜的退火行为,并研究了等径弯曲通道变形和退火后纯铜的显微硬度和显微结构变化。分析了ECAP应变量、退火时间和退火温度对超细晶铜的再结晶行为、抗软化性能的影响。结果表明:ECAP变形后的超细晶铜在退火过程中,表现出不连续再结晶现象;ECAP降低了铜的热稳定性,变形道次越高再结晶温度越低。退火后稳态晶粒尺寸随变形道次的增加而细化,硬度值随变形道次的增加而增大,回归分析表明,晶粒尺寸与硬度之间的关系符合Hall-Petch公式。     

等径转角挤压Cu-Cr-Zr合金的差热分析（英文）

对Cu-1Cr-0.1Zr合金在室温下进行16道次等径转角挤压(ECAP),挤压路径为B_c。利用差热分析研究合金中沉淀相的析出序列,计算每道次ECAP后合金储能、再结晶温度以及激活能。此外,对位错密度与电学性能之间的关系进行研究。结果表明:随着ECAP挤压道次的增加,合金中的储能增加,而再结晶温度则大幅度降低。     

12MnNb钢的ECAP变形及组织性能研究

室温下对12MnNb钢进行ECAP变形,累积等效应变达到4.通过光学显微镜、电子拉伸机等试验仪器设备,分析研究ECAP变形试样的显微组织特征及其演变规律,以及力学性能的变化规律.结果表明,C方式ECAP变形时,1道次的组织细化和强化效果最为显著,随后道次主要增加晶粒的取向差.经ECAP变形后,强度随变形道次的增加而增加,4道次后的抗拉强度达到895 MPa,并保持了较好的塑性,伸长率达到12.4%.     

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.