Thermodynamic optimisation of the Pb–Tl binary system

The phase diagram of the Pb–Tl binary system is experimentally well determined. Experimental thermodynamic values for all the phases involved are also available. For the liquid phase the temperature dependence of the enthalpy of mixing is also determined. In the present contribution, a consistent set of Gibbs energy functions of all the phases is obtained using the Redlich–Kister polynomial. The adjustable model parameters were determined by least-squares fit to the experimental data. A satisfactory agreement between experimental and calculated values is observed.     

The phase relationship in the Fe–Pb–Sb ternary system at 500 K

The phase relationship of the Fe–Pb–Sb ternary system at 500 K has been studied mainly by means of X-ray powder diffraction with the aid of differential thermal analysis and optical microscope. There are three three-phase regions, five two-phase regions and five single-phase regions in this ternary system at 500 K. No ternary compounds were found.     

液态金属储能电池中常用液态金属腐蚀研究进展

简要综述了液态金属储能电池中常用负极材料Li、正极材料Bi和Sb对与其接触的金属材料的腐蚀研究进展。根据近年来原子能反应堆以及液态金属储能电池等领域的液态金属腐蚀的研究成果,总结了金属材料在液态Li、Bi以及Sb中的腐蚀现象、腐蚀机理以及腐蚀影响因素,并提出了液态金属腐蚀的防护建议。     

Effect of dislocation density on the low temperature aging behavior of an ultra low carbon bake hardening steel

Strain aging was studied in an ultra low carbon (ULC) steel with a total carbon content of 20 ppm (wt.%) in order to identify the process stages and mechanism of bake hardening in this type of steel. The effects of dislocation density, varied by means of uniaxial tensile prestraining (1–10%) on the aging kinetics were investigated within an aging temperature range of 50–170°C. The aging was evaluated by means of strength measurements and the determination of interstitial carbon content after aging using a piezoelectric composite oscillator operating at 40 kHz. The interaction between interstitial carbon and dislocations was examined through amplitude dependent internal friction measurements. The influence of dislocation density on the aging behavior have been discussed with reference to the kinetics and mechanism of the aging process.     

The Zn-rich corner of the 450 °C isothermal section of the Zn–Bi–Fe–Ni quaternary system

Following up on recent studies of the isothermal section of the Zn–Fe–Ni, Zn–Fe–Bi and Zn–Bi–Ni ternary systems at 450 °C, the Zn-rich corner of the 450 °C isothermal section of the Zn–Bi–Fe–Ni quaternary system with the Zn being fixed at 93 at.% was determined experimentally using the equilibrated alloys approach. The specimens were investigated by means of scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). It was found there exist 4 two-phase regions, 5 three-phase regions and 2 four-phase regions. Two liquid L (Zn) and L (Bi) can coexist with T, ζ and δ-Ni in this isothermal section, no new phase was found in this study.     

Atmospheric Corrosion of Electroplates in Sea Climate: Protective-Decorative Functions and Service Life of Plates

This work finishes, sums up, and systematically generalizes the results of eleven papers (which were published in this journal starting from 1996) dealing with the corrosion behavior of all main classes of electroplates on carbon steel 10 and 62 brass, which are used in ship instrument engineering. The electroplates were tested for 14 to 20 years in marine atmosphere in containers simulating watertight and splashproof casings of ship instruments in cold (Murmansk), moderate humid (Vladivostok), and subtropical humid (Batumi) climate. The protective and decorative characteristics are tabulated for periods of 1, 5, 10, and 20 years and cover both monolayer metal or alloy coatings (Zn, Cd, Cd–20Sn, Ni, Cr, Sn–40Pb, Sn–1Bi, Ag, Au, and Pd) and multilayer coatings (Cu/Ni, Cu/Ni/Cr, Cu/(Sn–40Pb), Cu/(Sn–1Bi), Ag/Au, and Ag/Pd), including phosphated, chromated, hydrophobized, and lacquered coatings. The data on the summary gain in weight, the pure corrosion weight loss, and the weight of the products retained by the specimens are also generalized, as well as the service lives of the coatings according to the Branch Standard (OST) 5-9246-75 and State Standards (GOSTs) 9.012-73 and 9-311-87.     

16Mn(HIC)钢的冶炼

介绍了通过采用电炉粗炼钢水 ,钢包精炼炉真空精炼铸锭中间包芯杆吹氩真空浇注的工艺 ,生产出加氢用 1 6Mn( HIC)钢的过程 ,讨论了低硫钢冶炼的理论和生产实践     

Microstructural evolution during upward and downward transient directional solidification of hypomonotectic and monotectic Al–Bi alloys

Upward directional unsteady-state solidification experiments were performed with both a hypomonotectic Al–2.0 wt% Bi alloy and a monotectic Al–3.2 wt% Bi alloy. Besides, the monotectic composition (3.2 wt% Bi) was directionally solidified under downward transient heat flow conditions, which enables the effects of melt convection on the final microstructure to be evaluated since the collective downward movement of Bi-rich particles is favored in such case. This is due to the density differences between the two coexisting liquid phases. The thermal parameters such as cooling rate, growth rate and thermal gradient were experimentally determined by data collected from cooling curves recorded along the casting length. The monotectic features observed in the Al–3.2 wt% Bi alloy castings, i.e. the interphase spacing and Bi-rich particles diameter were correlated with the growth rate and thermal gradient. The cell spacing was experimentally determined for the Al–2.0 wt% Bi alloy as a function of both the cooling rate and tip growth rate. These experimental data were compared with the main predictive cellular growth models from the literature. A comparison between upward and downward unsteady-state solidification results for the interphase spacing and Bi-rich particles diameter has also been conducted.     

Nucleation of 3C–SiC on 6H–SiC from a liquid phase

The aim of this work is to elucidate the mechanism involved in the 3C–SiC formation during growth by a vapor–liquid–solid mechanism on 6H–SiC substrate. Polytype selection is shown to occur at the first stage of the experiments, before propane injection into the reactor. The contact of the seed with a Si–Ge melt during the initial heating ramp causes the formation of 3C–SiC islands on the seed surface, probably below 1200 °C. The proposed mechanism first involves a partial dissolution of the seed in a Ge-rich liquid which becomes C-supersaturated. Then the Si content of the liquid rapidly increases, which provokes the precipitation of the dissolved carbon in the form of 3C–SiC islands. When growth starts upon propane injection, these islands enlarge and coalesce to form a continuous 3C–SiC layer. If the growth temperature is too high (1550 °C), the initial 3C–SiC islands are dissolved and homoepitaxial layers are obtained.     

Investigation of liquid metal embrittlement of dual phase steel joints by electro-thermomechanical spot-welding simulation

ABSTRACT

A 3D electro-thermomechanical model is established in order to investigate liquid metal embrittlement. After calibration to a dual phase steel of the 1000?MPa tensile strength class, it is used to analyse the thermo-mechanical system of an experimental procedure to enforce liquid metal embrittlement during resistance spot welding. In this procedure, a tensile stress level is applied to zinc coated advanced high strength steel samples during welding. Thereby, liquid metal embrittlement formation is enforced, depending on the applied stress level and the selected material. The model is suitable to determine and visualise the corresponding underlying stresses and strains responsible for the occurrence of liquid metal embrittlement. Simulated local stresses and strains show good conformity with experimentally observed surface crack locations.     

核电站用不锈钢在液态Pb-Bi合金中的腐蚀行为研究进展

核电系统中,液态金属腐蚀问题是影响加速器驱动次临界系统(ADS)稳定服役的关键.概述了液态Pb-Bi合金和不锈钢在核电中的应用背景.在此基础上,重点综述了近年来常用不锈钢材料在液态Pb-Bi合金环境下的腐蚀行为,其中不锈钢在液态Pb-Bi合金中的腐蚀机制包括:(1)不锈钢中Ni元素在液态Pb-Bi合金中优先溶解而发生的...     

Dissolution behavior of zirconia-refractories during continuous casting of steel

Dissolution behavior of ZrO₂-graphite refractories used in a submerged entry nozzle (SEN) during continuous casting of steel was investigated using the rotating cylinder method. In the present work, the dissolution rate of the zirconia-graphite rod was determined by measuring the corrosion depth of the rod after a given immersion time. It was found that the dissolution rate was slow at the surface where molten flux alone is contacted, but much higher at the region that contacts the interface of the molten flux and liquid metal. The dissolution rate was influenced by the rotation speed of the rod, ZrO₂ content in the refractories, and the presence of Na₂O and fluoride (F⁻) in the mold flux. It is speculated that a cyclic process wherein zirconia dissolves into the molten flux and graphite dissolves into the liquid metal accelerates the dissolution at the flux-metal interface.     

Behavior and influence of Pband Biin Ag-Cu-Zn brazing alloy

0　ＩｎｔｒｏｄｕｃｔｉｏｎＰｂａｎｄＢｉａｒｅｃｏｍｍｏｎｉｍｐｕｒｉｔｙｅｌｅｍｅｎｔｓｉｎＡｇＣｕＺｎｂｒａｚｉｎｇａｌｌｏｙ[1].ＩｎｔｈｅｎａｔｉｏｎａｌｓｔａｎｄａｒｄｓｏｆＡｍｅｒｉｃａ,Ｊａｐａｎ,ＧｅｒｍａｎｙａｎｄＣｈｉｎａ(ｓｕｃｈａｓＡＮＳＩ/ＡＷＳＡ5.892,ＪＩＳＺ32611985,ＤＩＮ8513386,ＧＢ1004688),ｔｈｅｃｏｎｔｅｎｔｏｆａｌｌｔｈｅｉｍｐｕｒｉｔｙｅｌｅｍｅｎｔｓｉｎｂｒａｚｉｎｇａｌｌｏｙｉｓｒｅｓｔｒｉｃｔｅｄｔｏａｒａｎｇｅｎｏｔｅｘｃｅｅｄｅｄ0.15%[2].Ｂｕｔ,ｉｆｔ…     

Effect of current density on micro‐arc oxidation of Q235 steel and corrosion resistance in liquid Pb‐Bi

An attempt has been made to improve the corrosion resistance in liquid Pb‐Bi by micro‐arc oxidation (MAO), and the effects under different current densities on the corrosion resistance of the coatings were discussed. Scanning electron microscope, energy dispersive spectrometer, and X‐ray diffraction were used to analyze the surface morphology and phase constituents of the MAO coatings produced under different current densities. The corrosion resistance of the coatings was evaluated by studying the element changes and morphology evolution. The results show that the compactness of the ceramic coating decreases with the current density increasing. In contrast to the performance of matrix metal, the ceramic coating exhibited a much better corrosion resistance in liquid Pb‐Bi. Moreover, the ceramic coating produced under current density of 10 A/dm ² shows the best corrosion resistance.     

特种钎剂辅助铝/钢异种合金TIG熔-钎焊

采用铝硅钎料进行了铝/钢异种合金TIG熔-钎焊试验,开发出了适用于TIG电弧热源下的特种钎剂,通过高速摄影观察了液态钎料的润湿铺展行为,并分析了接头特性.结果表明,特种钎剂能够显著促进钎料的润湿铺展,钎剂成分(质量分数,%)为:改性的Noclock钎剂(KAlF4:K3AlF6,65:35)55～78,Zn10～20,Sn10～20,K2SiF62～5.液态钎料的铺展包括两部分:一是通过成形槽,沿钢背面进行铺展,获得良好的背面成形;二是沿坡口表面进行"上坡"铺展,实现焊缝正面成形.铝/钢TIG熔-钎焊接头具有熔焊与钎焊的双重性质,接头抗拉强度可达115.5MPa,断裂于焊缝/不锈钢界面层.     

High-Temperature Corrosion of A210-C Carbon Steel in Simulated Coal-Combustion Atmospheres

Corrosion of A210 C carbon steel was investigated under three different conditions: (1) using synthetic gas mixtures with varying amounts of O₂, SO₂, and HCl; (2) in the flue gas introduced from a coal-fired fluidized-bed combustor (FBC), with and without a deposit cover; and (3) within the freeboard of the FBC firing two different coals. Generally, the oxide scale formed in the temperature range of 370–560°C was mainly Fe₂O₃. The oxidation rate was significantly increased with an increase in temperature. In the synthetic gas mixtures SO₂ and HCl caused scale damage by weakening of the scale-metal interface. The combination of the gases can greatly accelerate the metal corrosion. In the FBC flue gas (condition 2), deposit additions exerted a significant effect on accelerating the metal corrosion. In the FBC freeboard tests (condition 3), the atmospheres containing a higher content of SO₂ and HCl increased the metal corrosion in comparison to corrosion in low-SO₂ and HCl-containing atmospheres. In the former case, an S-enriched phase or pits formed in the residual wastage at or near the metal. This may be the cause of wastage spallation. The HCl effect is discussed but is not conclusive. Moreover, in the FBC system, erosion and deposition appeared to play important roles in exaggerating metal recession.     

The adsorption and corrosion inhibition of some cationic gemini surfactants on carbon steel surface in hydrochloric acid

The adsorption and corrosion inhibition of the gemini surfactants 1,2-ethane bis(dimethyl alkyl (C_nH_2n+1) ammonium bromide) (designated as n−2−n, n=10, 12 and 16) on the steel surface in 1 M hydrochloride acid were studied using the weight loss method. It was found that the adsorption of the gemini surfactants on the steel surface is the main reason to cause the steel corrosion inhibition in hydrochloride acid, and the inhibition efficiency increases with the increase of surfactant concentration and reaches the maximum value near the CMC. A possible adsorption model of gemini surfactant onto the metal surface was also discussed.     

Carburization and metal dusting like attack of 9Cr-1Mo steel resulting from sulphide corrosion

The influence of two sulphur-bearing refinery environments: (1) liquid hydrocarbons with steam present, and (2) liquid hydrocarbons with hydrogen present on the corrosion behaviour of commercial 9Cr-1Mo steel has been investigated. It has been stated that the progress of sulphide corrosion is followed by carburization of this steel due to the release of carbon from the sulphur-attacked metal carbides and the diffusion of carbon ahead of the advancing corrosion front. The rapid progress of sulphide corrosion with the presence of hydrogen results in a steep carbon concentration profile and metal dusting of the carburized layer. When metal dusting starts, rapid acceleration of scale growth and localised metal thinning takes place.     

Study on interfacial heat transfer coefficient at metal/die interface during high pressure die casting process of AZ91D alloy

The high pressure die casting (HPDC) process is one of the fastest growing and most efficient methods for the production of complex shape castings of magnesium and aluminum alloys in today's manufacturing industry. In this study, a high pressure die casting experiment using AZ91D magnesium alloy was conducted, and the temperature profiles inside the die were measured. By using a computer program based on solving the inverse heat problem, the metal/die interfacial heat transfer coefficient (IHTC) was calculated and studied. The results show that the IHTC between the metal and die increases right after the liquid metal is brought into the cavity by the plunger, and decreases as the solidification process of the liquid metal proceeds until the liquid metal is completely solidified, when the IHTC tends to be stable. The interfacial heat transfer coefficient shows different characteristics under different casting wall thicknesses and varies with the change of solidification behavior.     

Mechanics and forming theory of liquid metal forging

1　INTRODUCTIONIntheliquidmetalforging process ,metalwasdirectlypouredintothediecavity ,thenmechanicalstaticpressurewasappliedbyanoilpresswhichmadetheunsolidifiedandquasi solidifiedmetalflowsolidifywithlittleplasticdeformation .Becauseliquidmetalorquasi solidifiedmetalareeasytoflow ,theprocesscanbecarriedoutwithrelativelylowerconsumptionofdeformationenergy .Comparedwithcasting ,thewayoffeedingwaschanged .Inthesolidificationofliquidmetal,thevolumecontractionwouldresultintheemergenceofthesh…