Mg—Zr,Mg—Zn及Mg—Zn—Zr合金的微观结构

研究了铸态和均匀化处理后的Mg—0.54Zr,Mg—5.68Zn及Mg—5.65Zn—0.50Zr合金的微观结构在三种合金中,均发现有{012}透镜片状孪晶Mg—0.54Zr合金经均匀化处理后产生了ZrH_2相Mg_7Zn_3相呈块状,主要分布于铸态Mg—5.68Zn合金晶界,测定为bcc立方结构(a=1.417nm);经均匀化处理后,Mg_7Zn_3相溶解,产生MgZn_2相铸态Mg-5.65Zn-0.50Zr合金由MgZn_2相和Zn—Zr化合物组成;经均匀化处理后,弥散析出了针状MgZn_2相     

合金元素对Mg-Er-Zn-Zr合金铸态组织和力学性能的影响

研究了合金元素Zn和Zr对Mg-Er-Zn-Zr合金铸态组织和力学性能的影响。结果表明,(Mg_(97.5)Er_2Zn_(0.5))_(99.82)Zr_(0.18)、Mg_(97)Er_2Zn_1和(Mg_(97)Er_2Zn_1)_(99.82)Zr_(0.18)合金都呈现典型的树枝晶结构。由于Zn元素的增加,(Mg_(97)Er_2Zn_1)_(99.82)Zr_(0.18)比(Mg_(97.5)Er_2Zn_(0.5))_(99.82)Zr_(0.18)的组织明显细化,二次枝晶臂的间距减小,第二相由非连续网状分布变成了片层状分布。Zr元素的添加使得合金晶粒细化,第二相呈现更加弥散分布,第二相组成没有发生变化,依然由X-Mg_(12)Er_1Zn_1相和(Mg,Zn)x Er相组成。随着Zn元素和Zr元素含量的增加,合金的力学性能明显提高。     

热挤压Mg-6Zn-xCu-0.6Zr(x=0,0.5,1.0,1.5)合金的显微组织及力学性能

对Mg-6Zn-x Cu-0.6Zr(x=0,0.5,1.0,1.5)合金进行了熔炼并浇注在金属模中,然后进行了挤压成形试验。结果表明:铸态合金随着Cu含量的增加晶粒逐渐细化,第二相含量增多,其组织由α-Mg、MgZn_2及Mg Zn Cu相组成。合金经挤压后力学性能明显提高,其中挤压ZK60合金的动态再结晶较弱,晶粒细化程度较小。铸态合金组织中的第二相在挤压过程中被打碎,并沿着挤压方向分布。挤压态合金晶粒细化程度明显,其平均晶粒尺寸可达到10~13μm。Mg Zn Cu相呈短棒状分布在晶界,而Mg Zn2相呈细小的颗粒状分布在基体上。挤压态合金力学性能改善的原因可归结为细晶强化、第二相弥散强化及固溶强化综合作用的结果。其中挤压态Mg-6Zn-1.0Cu-0.6Zr力学性能最优,其抗拉强度、屈服强度及伸长率分别达到320.22 MPa,240 MPa和11.48%。     

Mg-8Zn-1Ag-0.7Zr合金组织和力学性能研究

利用OM、SEM等手段对Mg-8Zn-1Ag-0.7Zr合金的微观组织、析出相成分和力学性能进行了研究,为工程应用提供参考。结果表明,Mg-8Zn-1Ag-0.7Zr合金以等轴晶方式凝固,铸态合金主要由α-Mg、Mg-Zn-Ag三元化合物和Zn_2Zr_3相组成,第二相主要集中分布在晶界上。热处理后,晶界上第二相的连续分布形态得到明显改善,Zn元素在基体中的含量变化明显。铸态时,Zn元素含量为3.09%,经固溶处理后,增加为8.24%。时效处理后,Zn元素含量下降至5.42%,起到很好的析出强化作用。T4态合金的抗拉强度、屈服强度和伸长率分别为311.4 MPa、147.4 MPa和13.7%,较铸态提高明显。经T6处理后,合金抗拉强度、屈服强度和伸长率为325.4 MPa、217.6 MPa和5.1%。     

固溶处理对(Mg_(96.5)Zn_(1.5)Er_2)_(99.82)Zr_(0.18)合金组织和硬度的影响

采用光学金相显微镜、SEM、EBSD、DTA分析以及硬度等试验手段,研究了固溶处理对(Mg_(96.5)Zn_(1.5)Er_2)_(99.82)Zr_(0.18)合金组织和力学性能的影响。结果表明,合金铸态及热处理态的微观组织均由α-Mg、X相和(Mg,Zn)_xEr相组成,对铸态的(Mg_(96.5)Zn_(1.5)Er_2)_(99.82)Zr_(0.18)合金进行固溶处理后,(Mg,Zn)_xEr相转变成弥散分布的X相。晶粒尺寸随着固溶时间和温度的增加而变大。与铸态相比,合金热处理后的硬度没有发生太大变化。     

Al-Zn-Zr三元系800℃等温截面的实验测定（英文）

利用扩散偶和平衡合金法,采用扫描电镜-能谱、X射线衍射和电子探针分析方法对Al-Zn-Zr三元系800℃等温截面进行实验测定。实验确定了13个三相区;三元化合物Zn_(50)Al_(25)Zr_(25)(T相)稳定存在于此等温截面,拥有比较大的成分区间(16.84%～55.1%Zn、18.02%～56.3%Al和26.0%～28.53%Zr,摩尔分数),并能与该体系中所有的二元化合物平衡共存。Zn在Zr-Al化合物Zr_3Al、Zr_2Al、Zr_3Al_2、Zr_4Al_3、ZrAl、Zr_2Al_3、Zr l_2和ZrAl_3中最大溶解度分别是7.5%、0.84%、0.33%、0.89%、0.91%、1.12%、0.64%和3.8%(摩尔分数);Al在Zn-Zr化合物Zn_3Zr、Zn_2Zr和ZnZr中最大溶解度分别是1.6%、1.3%和13.6%(摩尔分数)。     

MICROSTRUCTURES OF Mg-Zr,Mg-Zn AND Mg-Zn-Zr ALLOYS

Microstructural studies have been made on the Mg-0.54Zr,Mg-5.68Zn andMg-5.65Zn-0.50Zr alloys in the as-cast and homogenized states.The lenticular plates of{012}twins were found in three alloys.After homogenization,ZrH_2 phase formed in theMg-0.54Zr alloy.The Mg_7Zn_3 phase of cubic structure with a=1.417 nm distributes at thegrain boundaries of the Mg-5.68Zn alloy in the as-cast state and after homogenization,theMg_7Zn_3 phase dissolves and the MgZn_2 phase occurs.The as-cast Mg-5.65Zn-0.50Zr al-loy consists of MgZn_3 phase and Zn-Zr compounds.After homogenization,the dispersedacicular MgZn_2 phase may precipitate.     

Microstructure, Texture and Mechanical Properties of Extruded Mg-Zn-Zr Mg Alloy Profiles

通过X射线衍射分析、金相分析和力学性能测试对大尺寸ZK60镁合金挤压型材的微观组织、织构取向和室温力学性能进行系统研究。结果显示,挤压态ZK60镁合金中主要由α-Mg和Mg Zn2相组成,此外还有少量的Mg2Zn11和Zn2Zr3相。挤压变形后初始的粗大铸态组织沿着挤压方向被极大地细化和破碎,同时伴有部分动态再结晶发生。大部分晶粒的基面沿着挤压方向和横向排列而不是常规的挤压纤维状取向分布。沿着45o方向取样展现出最好的断裂伸长率,其中间和边部分别为28%和23%,而最大抗力强度则体现在沿着挤压方向拉伸样品在中间和边部分别为325和312 MPa。     

含LPSO相Mg_(94)Y_4Zn_1Ni_1合金的组织和力学性能

采用OM、SEM、TEM和电子万能试验机研究了Mg_(94)Y_4Zn_1Ni_1(at%)合金在铸态、退火、挤压和时效态的显微组织与力学性能。结果表明:铸态合金组织由胞状α-Mg相、网状18R LPSO相和块状Mg_(24)(Y,Zn,Ni)_5相组成。退火后,合金中未析出14H LPSO相。经挤压变形,18R LPSO相转变为长条状并沿挤压方向排列,挤压态合金的抗拉强度达到417 MPa,显著高于铸态和退火态合金。经过T5和T6时效处理,在合金的基体中析出大量细小的共格β'沉淀相,合金得到进一步强化。T5态和T6态合金的抗拉强度分别为434和432 MPa,屈服强度均高于300 MPa。     

Pd替代对Ti-Zr-Ni准晶合金结构的影响

针对Ti_(45)Zr_(38)Ni_(17)与Ti_(40)Zr_(40)Ni_(20)准晶合金用X射线衍射仪、透射电子显微镜与金相等手段研究了不同含量的Pd替代对其结构的影响.在吸铸态下,前一个合金形成了二十面体准晶相(IQC)与少量配位数为8的bccβ-(Ti,Zr)相,用2%Pd(原子分数,下同)对合金的Ti或Zr组元替代,抑制了β-(Ti,Zr)相析出并促使配位数为14的MgZn_2结构的简单六方C14 Laves相生成.而后一个合金中IQC相则与少量简单六方α-(Ti,Zr)共存,在2%Pd替代后α-(Ti,Zr)消失,生成了单一的IQC相,但当Pd替代量增加到6.7%或13.3%时,配位数为12的IQC相急剧减少而C14相大量析出,并在Ti_(40)Zr_(26.7)Ni_(20)Pd_(13.3)合金中生成了单一C14相.结果表明,添加中等尺寸的Pd原子有利于提高Ti-Zr-Ni合金的原子密堆性,使合金趋于生成高配位数的Laves相,这种相的Fermi面与Brillouin区的相互作用不显著,偏离了电子相的稳定机制.     

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).