铜磷非晶箔带钎料的制备及性能研究

利用液态单辊急冷法和传统铸造技术分别制备出成分相同的Cu68.5Ni15.7P6.5Sn9.3非晶箔带钎料和普通钎料,制得的非晶铜磷钎料箔带成型性良好,对折180°不断。将两种钎料在四种钎焊温度(660、670、680和690℃)和三种保温时间(5、10和15min)下与紫铜进行真空钎焊,借助DTA、XRD进行分析。结果表明,制备的非晶箔带钎料与相同成分的普通钎料相比,前者熔点低于后者;在同一钎焊条件下,前者润湿性优于后者。     

纯铜真空钎焊接头的组织及力学性能研究

利用快速凝固技术和传统铸造技术分别制备出成分相同的Cu-Ni-Sn-P非晶薄带钎料和普通钎料,将2种钎料在4种钎焊温度(660,670,680,690℃)和3种保温时间(5,10,15 min)下与纯铜进行真空钎焊试验,借助DTA,XRD,EDS和金相显微镜探讨了钎焊接头的界面微观组织结构及断口形貌,并通过拉伸试验评价了接头强度.研究结果表明:在680℃,15 min条件下,接头抗拉强度最高,非晶钎料的接头抗拉强度明显优于普通钎料,界面反应层由扩散区、残余钎料区组成.随着保温时间的延长和钎焊温度的升高,扩散深度增加,冶金作用增强,在基体深度方向明显表现为沿晶界优先渗透.     

非晶铜磷钎料真空钎焊的湿润性研究

利用快速凝固技术制造出Cu-Ni-Sn-P非晶薄带钎料,将此钎料分别在不同钎焊温度和钎焊时间下与紫铜进行真空钎焊,借助DTA、EPMA分析,探讨了在不同钎焊条件下钎焊接头的显微组织结构,及同成分非晶钎料与普通钎料的润湿性差异.研究表明,与普通钎料相比,非晶钎料润湿性明显提高,钎料与母材的相互扩散和冶金结合增强.     

Ag—Cu—Ti急冷钎料在Si3N4陶瓷上的润湿性研究

采用单辊急冷装置成功制备了3种成分的Ag-Cu-Ti箔带钎料,分析了其熔化特性和结构及其在Si3N4陶瓷上的润湿性.试验结果表明:上述急冷箔带钎料与常规钎料相比,熔化温度更低,熔化温度区间更窄,但其结构并不是非晶;在相同的工艺条件下,(Ag72Cu28)96Ti4在Si3N4陶瓷上的润湿性最佳;随钎焊温度和保温时间的增加,Ag-Cu-Ti急冷和常规钎料在Si3N4陶瓷上的浸润面积均增大;在相同钎焊工艺条件下,同成分急冷钎料在Si3N4陶瓷上的铺展面积明显大于常规钎料,这是由于急冷钎料的熔化特性和结构不同所导致的.     

急冷型SnAgCu系钎料箔带制备及物理性能测试

采用单辊法制备了急冷型SnAgCu系钎料箔带,对其进行了物理性能测试和显微组织分析,并与相同成分的常态钎料合金进行了分析比较,结果表明:采用单辊法制备急冷型SnAgCu系钎料箔带是可行的,所制备的钎料箔带熔化温度及同-液相线温度区间均低于相同成分的常态钎料合金,且其显微组织也更为细化.     

Au-20Sn贵金属钎料箔材的制备及性能研究

采用多层复合及扩散合金化工艺制备Au-20Sn贵金属钎料箔材,研究箔材的化学成分、熔化特性、力学性能、物相组成、组织形貌和微区成分,并采用真空钎焊工艺对所制备钎料箔材的钎焊性能进行研究。结果表明,采用多层复合及扩散合金化工艺制备的Au-20Sn钎料箔材脆性明显改善,能够在室温下冷冲裁加工成特定尺寸的预成型焊片;钎料箔材的化学成分和杂质含量符合设计要求,显微组织由连续且均匀分布的(Au Sn)和(Au₅Sn)两相组成;钎料熔程仅为3.1℃,在铜基材上润湿性和铺展性良好,钎焊铜接头力学性能较好。     

用非晶钎料加中间层连接Si3N4陶瓷的试验

采用TiZrCuB非晶钎料并用Cu箔为中间层连接Si3N4陶瓷,研究了钎料成分、钎焊工艺和中间层厚度等对接头室温和高温强度的影响.结果表明:采用Ti40Zr25CuB0.2非晶钎料和70μm厚的Cu箔中间层,在1 323 K,30 min及0.027 MPa压力下钎焊连接Si3N4陶瓷,其接头在室温下的四点抗弯强度最高...     

钛基快冷钎料高频感应钎焊TC4钛合金研究

利用快速凝固技术制备出4种不同成分配比的Ti-Zr-Cu-Ni基快冷薄带钎料,以TC4薄板作为金属造型材料,采用高频感应钎焊技术,层积成型长方体试样,对成型试样的力学性能和显微组织进行分析。结果表明,除Ti48-Zr25-Cu10-Ni11-Fe4-Sn1.5-Si0.5(at%)为快冷非晶钎料外,其余均为晶态钎料。在相同钎焊工艺参数下,非晶薄带钎料成型试样的拉伸强度远远高于由晶态钎料成型试样的拉伸强度。非晶钎料的钎焊接头组织主要由(Ti,Zr)_2(Cu,Ni)+(Ti,Zr)_(ss)共晶组织和富Zr的α-Ti固溶体组成;而快冷晶态钎料的钎焊接头组织主要由Ti基固溶体α-Ti组成,其晶粒粗大,晶内存在针状马氏体,导致脆性增加,拉伸强度降低。4种钎料的钎焊试样拉伸断口均呈人字纹形貌,为脆性断裂。     

真空钎焊TiAl基合金用Ti-Zr-Cu-Ni-Co-Mo钎料的钎焊性能（英文）

采用非晶和晶态Ti-25Zr-12.5Cu-12.5Ni-3.0Co-2.0Mo(质量分数,%)钎料对Ti-47Al-2Nb-2Cr-0.15B(摩尔分数,%)合金进行真空钎焊连接,对两种钎料的熔化行为、润湿铺展性、填缝隙能力以及由钎焊TiAl基合金所得的钎焊接头进行详细的研究。结果表明:与晶态钎料相比,非晶钎料具有更窄的熔化温度区间、更低的液相线温度和熔化激活能;同时,非晶钎料在Ti-47Al-2Nb-2Cr-0.15B合金表面上具有更优异的钎焊性。非晶和晶态两种钎料的钎焊接头均由两侧的界面反应层和中心钎焊层组成,非晶钎料钎焊接头的抗拉强度均高于相同钎焊工艺参数下的晶态钎料钎焊接头的抗拉强度,且在钎焊温度1273K下获得的钎焊接头的抗拉强度达到最大值254 MPa。     

瞬间液相焊非晶铜基钎料的制备及其性能研究

利用液态单辊急冷法制备用于铜及铜合金瞬间液相焊非晶铜基钎料--Cu68.5Ni15.7P6.5Sn9.3.制得的非晶铜磷钎料薄带具有良好的韧性,可以冲压成各种形状,钎焊工艺性能优良.将该钎料在4种钎焊温度(660℃、670℃、680℃、690℃)和3种保温时间(5 min、10 min、15 min)下与紫铜进行真空钎焊.结果表明,用非晶Cu68.5Ni15.7P6.5Sn9.3钎料焊接的接头有较高的强度.     

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.     

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。     

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).     

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.     

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.