7150 Al-Zn-Mg合金固态反应动力学参数的测定

采用差示扫描量热法（DSC）,在不同加热速率下研究7150 Al-Zn-Mg合金在水淬、自然时效和人工时效状态下的固态反应。DSC曲线上不同的放热和吸热峰对应着不同的固态反应阶段。随着加热速率的增加,各个峰位对应的温度也随之增加,表明这些固态反应是热力学活化和动力学控制的。通过测量不同时效时间下合金的硬度来评估合金的时效行为。通过分析DSC曲线各个峰位对应的热流,得到了合金固态反应的相变分数（Y）、相变速率（dY/dt）、相变函数（f（Y））和动力学参数（活化能Q、频率因子k0）。结果表明：所得到的这些动力学参数与已有文献所报道的结果吻合较好。     

吸铸法制备Mg-基大块非晶合金

采用吸铸方法首次制备出直径为3mm的Mg65Cu20Gd10Co5（原子百分比）四元玻璃态金属合金，并利用X射线衍射法（XRD）和差示扫描量热法（DSC）研究了其结构和热稳定性。实验结果表明，从XRD图谱看，该合金几乎均由非晶相组成，由DSC曲线分析知合金的玻璃转变温度Tg、晶化温度Tx值分别为413和473K，过冷液相区宽度△Tx值为60K,表明该合金具有较大的玻璃形成能力。     

CuBiAl合金相变动力学研究

采用DSC法研究了CuBiAl合金组织中（αCu）＋2γ（Al4Cu9）→β（AlCu3）的相变动力学。结果表明,该合金以10℃/min升温时的相变温度为562.12℃,合金的相变表观激活能为1 145.75 kJ/mol,相变起始激活能为2 744.58kJ/mol,随着相变体积分数的增加,其相变激活能逐渐减小。并在此基础上绘制了相变的体积分数与温度之间的关系曲线。     

水性封闭聚异氰酸酯/含羟基聚丙烯酸酯体系固化动力学

采用TGA/DSC同步热分析仪用非等温法对水性封闭型聚异氰酸酯/含羟基聚丙烯酸酯体系的热固化动力学进行了研究。选取4组不同的升温速率(5,10,15,20℃/min),得到TG和DSC曲线。在20℃/min升温速率下出现异常TG曲线后,研究了该升温速率对固化动力学研究的影响。结果表明,出现上述异常情况,对固化动力学结果影响较大,应不考虑该升温速率下的DSC数据。同时得到该水性封闭型脂肪族聚异氰酸酯/含羟基聚丙烯酸酯体系的固化反应表观活化能为47.88kJ·mol-1,表观频率因子为5.82×107 s-1,反应级数为0.90。     

2A14合金的连续冷却转变动力学曲线及其应用

测定2A14合金连续冷却转变动力学曲线(CCT图),并对该曲线进行应用研究.通过DSC分析和SEM组织观察确定2A14合金合理的固溶温度,采用动态电阻法测得固溶后合金连续冷却过程的电阻-温度曲线,根据曲线斜率变化判断相变信息,绘制2A14合金的CCT图,利用透射电镜(TEM)观察连续冷却过程中合金的组织转变.结果表明:2A14合金适宜的固溶温度为505℃;随着冷却速度的增加,相变开始温度先降低,在达到某冷却速度时骤升,然后持续增加;相变主要集中在140～380℃的温度区间发生,抑制相变发生的临界冷却速度稍大于3.8.5℃/s;在实验范围内,20 mm厚的2A14合金板适宜采用60℃或100℃水淬,参考所测CCT图制定分级淬火工艺,可以在最大限度减小淬火应力的同时,抑制第二相的析出.     

铸造Fe-Cr-B-Al合金相图计算及实验验证

利用相图计算软件Thermo-Calc计算并绘制了不同Al含量的Fe-10%Cr-B-x Al-C五元体系的垂直截面图,900℃平衡状态下组织中各相随Al含量的定量变化趋势图以及Fe-10%Cr-1.5%B-2%Al-0.3%C合金的平衡凝固过程图。选取了Fe-10%Cr-1.5%B-2%Al-0.3%C、Fe-10%Cr-1.5%B-4%Al-0.3%C两个成分的合金进行实验研究。利用DSC对合金的相变温度点进行检测,利用SEM-EDS、光学显微镜及XRD对不同相区的组织组成进行分析。结果表明:计算相图与实验测定结果无论是在相成分还是在相变温度上基本吻合,这也证明了Thermo-Calc计算软件中关于Fe-Cr-B-Al合金的热力学数据比较可靠,可以用来指导合金的成分及热处理工艺的设计。     

马氏体转变（十四）

5.6.1.2Cu-Zn和Cu-Zn-Al合金Cu-Zn二元合金的相图如图26[78],其中β相为电子浓度为3/2（21/14）的化合物CuZn（50at%）为基的固溶体。β相高温时为无序相（A2点阵）,具有bcc结构,在456~468℃转变为有序bcc的β（或β2）（B2或CsCl点阵）相。由于无序有序转变温度较低,需加入第三组元Al、Ge、Si、Sn或Be使之提高。加入6wt%Al的Cu-Zn-Al三元相图的垂直截面示于图27[78]。β相区大大移向低Zn浓度区域。淬火可使获得有序的β2相,并发生B2DO3的有序转变[78]。     

Ti100-xNix(x=40～70)形状记忆合金的Ni含量-时效工艺-相变行为关系图及其应用

采用示差扫描量热仪(DSC)建立了Ti_100-xNi_x(x=40～70)形状记忆合金的Ni含量-时效工艺-DSC曲线关系图、Ni含量-时效工艺-相变类型关系图、Ni含量-时效工艺-相变温度关系图、Ni含量-时效工艺-相变热滞关系图、Ni含量-时效工艺-相变潜热关系图。利用这些图能解决两类问题：当TiNi形状记忆合金的Ni含量、时效温度和时效时间已知时，可预测该合金的DSC曲线、相变类型、相变温度、相变热滞和相变潜热；当期望TiNi形状记忆合金具有某个DSC曲线、相变类型、相变温度、相变热滞或相变潜热时，可设计该合金的Ni含量、时效温度和时效时间。     

Mg—B体系成相热力学研究

采用热力学计算法、扩散偶法以及差示扫描量热法（DSC）对Mg-B体系成相行为进行了研究。热力学计算显示，Mg-B体系固-固反应在298K-923K温度范围内均可以发生。扩散研究显示，Mg-B之间的固态反应是通过Mg向B扩散实现的。DSC研究表明，Mg-B体系在升温过程中，分别在527．12℃，650．73℃和660．82℃，先后发生了固．固反应，Mg熔化以及液-固反应。在综合考虑扩散研究、热力学研究结果的基础上，提出了MS-B体系反应模型。     

共沉淀法合成新型阴极材料Ba0.5Sr0.5Co0.8Fe0.2O3-σ

草酸共沉淀法合成了中温固体氧化物燃料电池（ITSOFC）新型阴极材料Ba0.5Sr0.5Co0.8Fe0.2O3-σ（BSCF）。XRD，DSC和SEM结果显示：经过900℃煅烧2h后，产物的钙钛矿结构已经初步形成，但由于晶化不完全，衍射峰强度相对较弱，且存在杂相；随着煅烧温度提高到1200℃后，产物中杂相消失，晶体结构转变为单一的立方型钙钛矿，颗粒大小基本在2μm～3μm；BSCF与Ce0．8Sm0．2O1．9（SDC）混合物（质量比1：1）在1000℃下热处理24h后未发现杂相，表明BSCF与SDC具有良好的化学相容性。     

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.     

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。     

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.     

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.     

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).     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.