Effect of manganese on sintering processes in the Ti-Fe system

Conclusions The behavior of Ti-Fe-Mn specimens under conditions of sintering at temperatures above the eutectic point is analogous to that of Ti-Fe and Ti-Fe-Ni specimens: The changes in the linear dimensions of compacts and the magnitude of exothermic effects depend on the rate of heating to the sintering temperature. At high rates of heating the linear dimensions of Ti-Fe-Mn specimens change in a stepwise manner (their shrinkage decreases). During slow heating a decrease in the shrinkage of Ti-Fe-Mn specimens, unlike that of Ti-Fe and Ti-Fe-Ni specimens, is followed by its increase.Translated from Poroshkovaya Metallurgiya, No. 1(277), pp. 15–18, January, 1986.     

Effect of nickel on sintering processes in the Ti-Fe system. Part I

Conclusions Diffusional interaction in the Ti-Fe-Ni system is more vigorous than that in the Ti-Fe system. The temperature of the first ternary eutectic point in the Ti-Fe-Ni system, determined by the contact melting method, is 1040°C. During the sintering of compacts from a mixture of Ti, Fe, and Ni powders at temperatures above the eutectic point growth is observed, whose extent depends on the sintering temperature and the particle size of the powder employed: The smaller the particle size and the higher the sintering temperature, the smaller is the growth.Translated from Poroshkovaya Metallurgiya, No. 7(247), pp. 34–39, July, 1983.     

The kinetics of diffusion processes in the nickel-aluminum composition

The kinetics of diffusion processes on interlayer boundaries of the three-layered composites aluminum (AD1) + nickel (NP1) + aluminum (AD1) obtained by explosion welding with subsequent cold rolling is investigated. The phase composition of the diffusion region is established.     

Ion-plasma processes of the production of diffusion aluminide coatings

A novel ion-plasma process for ecologically safe formation of diffusion aluminide coatings on a substrate made of a superalloy, which has advantages as compared to the well-known thermodiffusion processes of their production, is described. The ion-plasma process is shown to provide the formation of diffusion aluminide coatings on the surface of a superalloy substrate according to various technologies. Owing to alloying with one or several elements from the series Y, Si, Cr, Hf, B, Co, etc., ion-plasma diffusion coatings have higher protective properties than analogous coatings produced by the traditional methods of powder, slip, and gas-circulating aluminizing.     

Effect of Zn concentration on diffusion induced grain boundary migration in Cu -Zn system

Cu-Zn alloy system with three different compositions has been chosen to study the time, temperature and composition dependence of the Diffusion Induced Grain boundary Migration (DIGM) in the temperature range of 277–427°C. The grain boundary migration follows parabolic rate law as a function of time. The diffusivity, D_bα, was calculated from concentration-distance profile using growth rate, v. The activation energy for diffusion is found to be 101kJ/mol which is nearly half of the activation energy required for volume diffusion indicating that preferential grain boundary diffusion is more favorable than volume diffusion leading to grain boundary migration in Cu-Zn system.     

Kinetics of diffusion in the Nb-Al system

Diffusion kinetics were studied by varying the time and temperature (800° to 1300°C) of dipping solid niobium into molten aluminum. It was found by X-ray diffraction analysis that only the Al₃Nb phase forms at the surface of the niobium specimen and that the thickness of this layer for a given dip temperature varies parabolically with time. The activation energy and the preexponential factor of the diffusion parameter, (δD) were found to be 36.5 ∓ 0.45 kcal per mole and 2.0 ∓ 0.34 sq cm per sec, respectively.     

碳化对混凝土中氯离子扩散的影响

混凝土与静浆快速碳化0,14,28d后浸泡到3.5%NaCl溶液中650d,测试了混凝土不同深度的自由氯离子、总氯离子含量,计算出混凝土的表观氯离子扩散系数和氯离子结合能力;采用压汞法测试了不同腐蚀制度下静浆表层的孔结构,利用DSC分析了静浆的腐蚀产物.结果表明:混凝土碳化后浸泡到腐蚀溶液中,增加了混凝土中的氯离子含量,提高了混凝土表观氯离子扩散系数,降低了混凝土对氯离子的结合能力;且随碳化时间的增加,变化幅度变大.快速碳化粗化了混凝土的孔结构,其大于30nm的毛细孔数量增加了11%,最可几孔径增加了17nm;降低了混凝土中Friedel'S生成量,以及混凝土对氯离子的化学结合能力.     

Effect of high-energy electron irradiation of a multilayer W-Mo system on the spectral characteristics of thermowave processes

A method is developed to analyze the state of the interface in a multilayer metallic system; it is based on spectral analysis of a heat-transfer coefficient. A coefficient of correlation is used to find the relation between the spectral characteristics and the thermal conductivity of the interphase interface. The change in the coefficient of correlation induced by 10-MeV electron irradiation of a multilayer W-Mo system is studied.     

Effect of technological factors on the diffusion kinetics in the copper-aluminum composite

An investigation is performed on the effect of thermal treatment conditions, furnace atmosphere, and technological protective coatings of various compositions on the formation of the phase composition of diffusion layers in welding zones of a layered intermetallic composite of the Cu-Al system produced by complex technology.