含氮马氏体的低温时效

采用纯铁片渗氮,淬火及低温回火制得了含有α″－Ｆｅ１６Ｎ２,γ′－Ｆｅ４Ｎ,含氮马氏体以及残余奥氏体等不同组分的Ｆｅ－Ｎ薄片。利用显微硬度计,Ｘ射线衍射仪及透射电镜分析了含氮马氏体在不同温度下的时效过程以及亚稳氮化物,α″－Ｆｅ１６Ｎ２相的析出特征。     

纯铁高温两段离子渗氮层内的反常组织

采用ＳＥＭ和Ｘ射线薄膜掠射装置测定了工业纯针在Ｆｅ－Ｎ共析温度以上两段高离子渗氮层的组织形态和γ、α两相沿渗层深度的分布。发现对应渗层的亚析成分存在网状分布的γ相并构成富γ相域；带状的α相区与基体邻接。     

离子束辅助沉积Fe－N薄膜的相形成SCIEI

用离子束辅助沉积方法合成Ｆｅ－Ｎ薄膜，用离子束背散射和Ｘ射线衍射方法分析薄膜成分和结构．结果表明，薄膜的组分（α－Ｆｅ，ζ－Ｆｅ２Ｎ，ε－Ｆｅ（２－３）Ｎ，γ＇－Ｆｅ４Ｎ相等）取决于沉积参数。给出了沉积温度和Ｎ／Ｆｅ原子到达比组成的相区域图．     

离子束辅助沉积Fe－N薄膜的相形成

用离子束辅助沉积方法合成Ｆｅ－Ｎ薄膜，用离子束背散射和Ｘ射线衍射方法分析薄膜成分和结构．结果表明，薄膜的组分（α－Ｆｅ，ζ－Ｆｅ２Ｎ，ε－Ｆｅ（２－３）Ｎ，γ＇－Ｆｅ４Ｎ相等）取决于沉积参数。给出了沉积温度和Ｎ／Ｆｅ原子到达比组成的相区域图．     

GCr15钢超塑表面合金化层组织的研究

用扫描电镜，Ｘ射线衍射仪、Ｘ射线能谱仪和透射电镜研究了ＧＣｒ１５钢表面在超塑变形过程中Ｎｉ、Ｃｒ合金化形成的组织结构。结果表明，合金化白亮层由α－Ｆｅ、γ、Ｎｉ２Ｆｅ、（Ｆｅ，Ｃｒ）７Ｃ３等组成，白亮层具有很高的硬度。     

含氮马氏体的低温时效

采用纯铁片渗氮、淬火及低温回火制得了含有α″Ｆｅ１６Ｎ２、γ′Ｆｅ４Ｎ、含氮马氏体以及残余奥氏体等不同组分的ＦｅＮ薄片。利用显微硬度计、Ｘ射线衍射仪及透射电镜分析了含氮马氏体在不同温度下的时效过程以及亚稳氮化物α″Ｆｅ１６Ｎ２相的析出特征。     

高速电弧喷射沉积Fe3Al涂层研究

采用自行研制的电弧喷涂Ｆｅ３Ａｌ合金粉丝材料,成功地用高速电弧喷涂技术制备出Ｆｅ３Ａｌ化合物涂层运用能谱技术（ＥＤＸＡ）、Ｘ射线衍射仪（ＸＲＤ）、扫描电子显微镜（ＳＥＭ）和图像分析仪对涂层成分、显微组织、涂层相结构和组成进行了分析,结果表明,支由以Ｆｅ－２９Ａｌ为主的Ｆｅ３Ａｌ和少量Ｆｅ３Ａｌ基体相和约２０％的α－Ａ１２Ｏ３相组成。对比研究了Ｆｅ３Ａｌ涂层和电站锅炉水冷壁材料２０Ｇ的６５０℃氧化动     

La在脉冲离子渗氮表层中的扩散及其对氮分布和相结构的影响

研究了在脉冲等离子体稀土渗氮过程中稀土元素Ｌａ对氮浓度分布和相结构的影响,揭示了Ｌａ在化合物层中的扩散规律,结果表明：与常规离子渗氮相比稀土绵添加,提高了表面氮浓度,随处理时间的延长而增加,当渗氮时间从２ｈ增加至２４ｈ时,化合物导上ε－Ｆｅ２－３Ｎ（ε）转化为ε－Ｆｅ２－３Ｎ和γ‘－Ｆｅ４Ｎ（γ’）双相,此外,Ｌａ可以扩散进入ε和γ‘相中,Ｌａ的扩散规律受制于化合物的γ’－Ｆｅ４Ｎ的比例,随时间延     

(Sm,Zr)Fe_7N_x α-Fe复合磁体的组织和磁性

（Ｓｍ,Ｚｒ）Ｆｅ７Ｎｘ＋α－Ｆｅ复合磁体的组织和磁性（Ｓｍ,Ｚｒ）Ｆｅ７Ｎｘ＋α－Ｆｅ微细复合磁体既具有高磁性又具有很好的而蚀性,作为新型稀土粘结磁体材料而受到重视。这种复合磁体的磁特性,受其组织状态的影响很大,因此利用热分析法、Ｘ射线衍射、透射电...     

真空热处理对W—7Ni—3Fe高密度合金力学性能的影响

研究了真空热处理对Ｗ－７Ｎｉ－３Ｆｅ高密度合金力学性能的影响。结果表明，真空热处理可使合金试样的抗拉强度及伸长率显著提高，但对冲击韧度影响不大。通过对合金试样断口形貌的扫描电镜（ＳＥＭ）观察及对试样断口表面合金元素价态的Ｘ射线光电子能谱（ＸＰＳ）分析，探讨了真空热处理对合金力学性能影响的机理。     

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.     

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).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

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.     

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.     

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.