GCr15钢超塑表面合会化层组织的研究

要用扫描电镜，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ａ－Ｆｅ、ｒ、Ｎｉ２Ｆｅ、（Ｆｅ，Ｃｒ）７Ｃ３等组成，白亮层具有很高的硬度。     

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。     

常压等离子束扫描16Mn表面合金化及淬火研究

用高能等离子束在常压下快速扫描涂敷合金粉末的１６Ｍｎ钢表面,实现了表面合金化及自激冷淬火,透射电镜分析表明,合金化层组织细小,产生了ＦｅＢ,Ｆｅ３Ｂ,Ｆｅ３（Ｓｉ,Ｂ）等合金相,１６Ｍｎ钢经上述复合处理后表层硬度可达５９５ＨＶ０．０５（５６ＨＲＣ）。     

M2高速钢激光表面钴合金化的研究

研究了Ｍ２高速钢激光表面Ｃｏ合金化的组织和性能。着重分析了激光工艺参数对合金化层中Ｃｏ浓度的影响。结果表明，采用激光表面合金化，可使Ｍ２高速钢表面Ｃｏ浓度在２％－５％。合金化层听Ｃｏ浓度主要与激光扫描速度和预沉积的Ｃｏ的厚度有关。退火态的Ｍ２高速钢在激光Ｃｏ合金化后，硬度可达８００ＨＶ。经淬火回火处理后，硬度可达１１５０ＨＶ，明显高于未进Ｃｏ合金化的Ｍ２高速钢。     

常压等离子束扫描16Mn表面合金化及淬火研究

用高能等离子束在常压下快速扫描涂敷合金粉末的１６Ｍｎ钢表面,实现了表面合金化及自激冷淬火。透射电镜分析表明：合金化层组织细小,并产生了ＦｅＢ、Ｆｅ３Ｂ、Ｆｅ３（Ｓｉ,Ｂ）等合金相。１６Ｍｎ钢经上述复合处理后表层硬度可达５９５ＨＶ００５（５６ＨＲＣ）。     

加氮合金化的高强度形状记忆钢

加氮合金化的高强度形状记忆钢Ｆｅ－Ｍｎ－Ｓｉ形状记忆合金的性能通过加Ｃｒ、Ｎｉ、Ｃｏ、Ｃ合金化可以得到改善，加Ｎ合金化可显著改善其形状记忆、力学性能和耐蚀性。加氮的形状记忆钢具有可回复应变２．５～４．２％和高达３３０ＭＰａ以上的回复应力，屈服强度可高...     

生产电解二氧化锰用钛合金阳极的抗钝化性能

研究了Ｔｉ－１．５Ｎｉ、Ｔｉ－０．５Ｆｅ、Ｔｉ－１．５Ｎｉ－０．５Ｃｕ、Ｔｉ－１．５Ｎｉ－０．５Ｆｅ－０．３Ｃｕ４种合金在９５℃，４０ｇ／Ｌ Ｈ２ＳＯ４＋８０ｇ／Ｌ ＭｎＳＯ４电解二氧化锰溶液中作阳极时的抗钝化性能。研究表明：以上４种合金都具有比ＴＡ２优异的抗钝化性能，ＴｉＮｉＦｅ的最为优异，在电流密度低于８０Ａ／ｍ＾２时，阳极表面不生成氧化膜，析出相Ｔｉ２Ｎｉ对提高抗钝化性起关键作用。ＴｉＮｉＦ     

WC—高碳铬铸铁铸渗层耐磨性与显微结构的研究

在ＭＭ２００磨损试验机上研究了铸渗层的抗磨粒磨损性能。利用透射电镜研究了铸渗层的组织结构。研究结果表明,铸渗层的耐磨性比淬火态４５钢提高３倍,比ＱＴ６００－３提高４倍,渗层中块状颗粒ＷＣ和（Ｃｒ,Ｆｅ）７Ｃ３片状颗粒结合牢固,且（Ｃｒ,Ｆｅ）７Ｃ３颗粒中有孪晶,ＷＣ颗粒中有位错。     

45钢激光表面合金化熔池立体对流模型探讨

对４５钢上Ｆｅ基合金粉末激光表面合金化熔池，从三个不同的侧面进行了分析，在理论分析和试验的基础上，提出了激光表面合金化熔池的立体对流模型，同时，对合金层进行成分分析。结果表明：正由于熔池内部的对流，使合金层成分在宏观上趋于均匀。     

45钢激光表面合金化熔池立体对流模型探讨

对４５钢上Ｆｅ基合盒粉未激光表面合金化熔池，从三个不同的侧面进行了分析。在理论分析和试验的基础上，提出了激光表面合金化熔池的立体对流模型，同时，对合金层进行成分分析。结果表明：正由于熔池内部的对流，使合金层成分在宏观上趋于均匀。     

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.