减摩钢的组织结构分析

利用金相显微镜、能谱和透射电镜对减摩钢进行观察和分析，结果表明：该试样基体组织为均匀颁布的层片状珠光体．其中每一个片层厚度为0．2μm，试样中存在磷共晶、块状（Fe，Mn）S和断续网状渗碳体。其中主要是磷共晶和（Fe,Mn）S的自润滑作用降低了摩擦系数。     

Al-5Mg-0.8Mn合金的凝固组织研究

通过重熔-凝固试验,研究了接近AA5083合金成分的Al-5Mg-0.8Mn合金的凝固组织。结果表明:Fe和Si元素对Al-5Mg-0.8Mn有重大影响,促进了金属间化合物Al_6(Fe,Mn)和Mg_2Si的形成。当Fe、Si含量很低时,Al-5Mg-0.8Mn合金的凝固组织非常简单,只是在α-Al基体上零星散落着一些细小的Al_6(Fe,Mn)共晶相。当Fe、Si含量较高时,合金中不但出现了大量粗大的Al_6(Fe,Mn)和Mg_2Si共晶相,而且,共晶相Al_6(Fe,Mn)呈现多种不同的形态,而Mg2Si相主要呈汉字状。     

基于共晶相量化的6082铝合金的最佳均匀化制度

采用差示扫描量热仪、金相显微镜、扫描电子显微镜及能谱分析等方法,通过对6082铝合金的铸态和均匀化态的显微组织观察和共晶相的量化统计研究,确定了6082铝合金的最佳均匀化制度。结果表明:6082铝合金铸态组织中存在着大量的非平衡凝固的Mg2Si共晶相和β-Al(Mn,Fe) Si相共晶相。经过560℃10 h均匀化后,Mg2Si共晶相溶解入α(Al)基体中,β-Al(Mn,Fe)Si共晶相向α-Al(Mn,Fe)Si相转变。     

激光辐照对渗硼后65Mn钢组织和性能的影响

采用激光辐照对渗硼后65Mn钢进行了表面改性,研究了激光重熔和激光淬火两种典型辐照处理后的微观组织、表层脆性和耐磨性。结果表明:65Mn钢渗硼试样,经激光重熔后其表层组织为夹杂着共晶硼化物的亚共晶组织(硬度约为880 HV),而经激光淬火后其表层组织是以Fe2B相为主的硼化物(硬度约为1100 HV),两种辐照处理后在次表层均形成了具有良好支撑作用的针状马氏体区;同时,两种激光辐照处理对表层脆性均有着较好的改善作用,脆性等级由原渗硼层的4级降低至1~2级;此外,经激光淬火后65Mn钢渗硼试样的耐磨性,不仅远好于激光重熔处理后的试样,而且也好于激光辐照处理前的渗硼试样。     

流变铸造不同铁含量过共晶Al-Si合金在干摩擦条件下的磨损行为（英文）

研究铁含量对流变铸造过共晶Al-17Si-2Cu-1Ni合金在干摩擦条件下磨损行为的影响。磨损测试是在销-盘式摩擦磨损试验机上进行的。结果表明,在同等载荷下,流变铸造合金试样比传统重力金属型铸造试样的磨损率小。细小颗粒状δ-Al_4(Fe,Mn)Si_2相和多边形状α-Al_(15)(Fe,Mn)_3Si_2相有助于提高流变铸造合金的耐磨性。随着细小富铁相体积分数的增加,流变铸造合金试样的磨损率减小。此外,随着载荷从50增大至200 N,流变铸造合金试样的磨损率增大。对于含3%Fe的流变铸造合金,在低载荷(50 N)时,磨损机制以氧化磨损为主;在高载荷时,磨损机制以氧化磨损和剥层磨损的联合作用为主。     

T10钢自蔓延高温渗硼共晶化的研究

采用自蔓延高温渗硼共晶化技术在T10钢表面获得了具有共晶组织的渗硼层。渗层最大厚度可达1．6mm，渗层与基体呈冶金结合状态。渗层物相主要由α—Fe、Fe3(C，B)及少量的Fe23(C，B)6相构成，其中，Fe3(C，B)相构成花纹状共晶的骨架，α—Fe相则分布于其中，从而赋予渗层以良好的强度、硬度与韧性。     

热处理及Mn元素对汽车发动机用过共晶铝硅合金组织的影响

针对传统铸造法加工过共晶铝硅合金组织粗大,合金性能恶化的问题,研究了热处理和元素Mn对过共晶铝硅合金中粗大富铁相的细化作用。研究表明:过共晶铝硅合金Al-16Si-2Fe经T6热处理工艺后,共晶硅形貌从短针状变为粒状,粗大针状富铁相β-Al_5Fe Si形貌未发生变化,热处理无法达到细化富铁相的目的。元素Mn对共晶铝硅合金Al-16Si-2Fe中富铁相形貌改善明显,可使粗大富铁相β-Al_5Fe Si转化为细小颗粒状和枝晶状的Al_(15)(Fe Mn)_3Si_2相。当Mn含量为2wt%时,Al-16Si-2Fe合金中富铁相细化效果最佳。     

Al-22Si-3Fe-1.8Mn合金中的四元富铁相研究

利用X射线衍射仪、扫描电镜(带EDS)和金相显微镜对Al-22Si-3Fe-1.8Mn合金进行研究.结果表明:在铸态试样中存在晶体结构分别与Al8Fe2Si、Al9Fe2Si2和Al3FeSi2晶体结构相同的三种四元富铁相,并确定了其中两种相的化学式分别为Al12Si2Fe2Mn、AL42.5Si11Fe4.7Mn.通过萃取态试样确定了另一种富铁相的化学式为Al15.97Sil4.8.82Fe4.24Mn,并且该相为Al-22Si-3Fe-1.8Mn合金中最先析出的高温相.     

Mn/Cr复合变质对15%Mg_2Si/再生A356-1.5%Fe基复合材料中富Fe相形态的影响

利用Mn/Cr复合对15%Mg_2Si/再生A356-1.5%Fe基复合材料进行变质处理,利用SEM、EDS、热分析等方法研究Mn/Cr添加量对复合材料中富Fe相形态的影响规律及其机制,并探讨Mn/Cr添加量对复合材料各物相的凝固结晶特性顺序的影响。富Fe相形态随着Mn/Cr添加量的变化而改变,未变质时,富Fe相形态主要为长针状;Cr(1.0%,质量分数)含量较多时,富Fe相形态主要为骨骼状;Cr和Mn含量均为0.5%时,富Fe相形态主要以颗粒状为主,此时变质效果最佳;而当Mn(1.0%)含量较大时,富Fe相形态则主要呈现花瓣状。未变质复合材料凝固结晶顺序为:初生Mg_2Si相(649.8℃)、α-Fe相(629.8℃)、π-Fe相(618.3℃)、Al+Mg_2Si共晶(578.3℃)、Al+Mg_2Si+Si三元共晶(556.7℃);随着Mn含量的不断增加,富Fe相的初始形核温度与基体形核温度差增大,其形核生长时间增加,Fe相尺寸不断增大,数目相对减少。     

Mn/Fe摩尔比对A356铸造铝合金富铁相形态的影响

在含1.0%Fe(质量分数)的A356铝合金中添加不同含量的Mn,采用OM、SEM、EDS及DSC等分析方法研究Mn/Fe摩尔比对富铁相形态的影响及其规律,探讨添加Mn后A356-1.0Fe合金中物相的凝固顺序。结果表明:随着Mn/Fe摩尔比的提高,富铁相形态的演变顺序为:针状→汉字状→树枝状→星形→多边形状,当Mn/Fe摩尔比超过1.2时可基本消除针状铁相。富铁相中(Fe,Mn)/Si摩尔比随富铁相形态的凝固先后顺序逐渐增加,分别为针状富铁相中(Fe,Mn)/Si摩尔比为0.5~0.7,树枝状和汉字状富铁相中(Fe,Mn)/Si摩尔比为的1.2~1.7,星型和多边形富铁相中(Fe,Mn)/Si摩尔比为1.9。富铁相的平均晶粒尺寸和体积分数随Mn/Fe摩尔比的增加先增加后减小,而后再增加。其中当Mn/Fe摩尔比为1.0时,富铁相的平均晶粒尺寸和体积分数均为最小,与A356-1.0Fe合金的相近。此外,Mn的添加有利于提高共晶相和α(Al)基体相的形成温度,有利于多边形富铁相的形成。     

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.