Structure of high-temperature nickel alloys after time heat treatment of the melt

The strict requirements imposed on articles made of high-temperature nickel alloys require improvement of their composition and technology in all stages of metallurgical production. However, at present the degree of their alloying has become practically maximum. The service characteristics of high-ternperature alloys can hardly be improved further by correcting their chemical composition. The problem is solved most successfully by developing new technological regimes of melting and casting. It is economically expedient to use new technological approaches to the already well investigated and tested compositions. The present work is concerned with the effect of the so-called time heat treatment (THT) of liquid metal on the macro- and microstructure of high-temperature nickel alloys used in the production of equiaxial and single-crystal castings.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 6, pp. 6–8,June, 195     

Evolution of intermetallic phases of Al-Zn-Mg-Cu alloy during heat treatment

Al-Zn-Mg-Cu alloy is a favorable choice for aerospace applications requiring good combination of strength and toughness, which is greatly influenced by the coarse intermetallic particles. The evolution of intermetallic particles in an Al-Zn-Mg-Cu alloy during heat treatment was studied by field emission gun scanning electron microscopy （FEG-SEM） and X-ray diffractometry（XRD）. The results show that there are lamellar eutectic structure （α（Al）＋Mg（Zn,Al,Cu）：） and Al7Cu：Fe particles in the solidified structure. The Al7Cu2Fe particles are embedded in the eutectic structure. The content of eutectic structure decreases with the increase of holding time and disappears after 24 h. The size and morphology of Al7Cu：Fe particles exhibit no change during the heat treatment. It is found that the AI：CuMg phase is formed during the treatment at 460 ℃. A transformation process from the primary eutectic phase Mg（Zn,Al,Cu）2 to Al2CuMg is observed, and the transformation mechanism and kinetics are analyzed, The AI：CuMg constituents form in the primary Mg（Zn,Al,Cu）： phase, and grow along the eutectic microstructure.     

Dissolution of excess phases in structural steels in heat treatment

The effect of thermodynamic and kinetic factors on the degree of dissolution of carbide, nitride, and carbonitride segregations in steels is considered and the possibilities of modeling the dissolution process using analytical, semianalytical, and numerical methods are analyzed.     

]Structure and properties of low carbon steels after heat treatment and heat cycling with plastic deformation

Leningrad Polytechnic Institute. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 12, pp. 5–8, December, 1989.     

Structure and microhardness of the surface layers of iron-carbon alloys after laser heat treatment

Laser radiation is widely used for heat treatment of surfaces of parts. Its special features consist in localizability of the treatment zone, the possibility of strengthening rather inaccessible regions, and, in some cases, elimination of the tempering operation. For the laser treatment to be highly efficient we need data on the effect of the regime and type of laser on the properties of surfaces of various steels and alloys, which are rather scarce in the literature. The aim of the present work consists in analyzing and generalizing results obtained in investigations of the structure and structural and phase transformations in treatment of steels and cast irons by radiation of various lasers.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 2, pp. 20–25, February, 1996.     

Structure and properties of alloys and coatings with ordered β-phase after heat treatment

Ways for changing the structure and properties of alloys of the Cu-Zn-Fe-Mn-Si system due to formation of required amount of CuZn ordered β-phase with specific grain size during heat treatment and for raising the endurance of alloys of the Fe-Cr-Al system due to formation of ordered DO ₃ -or B2-phases in the α-solid solution during aluminizing are considered. The effect of the composition of alumosilicide β-coatings on their protective properties is analyzed, including their resistance to cracking upon rapid cooling. The effect of boron on the endurance of such coatings is studied. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 5, pp. 30–36, May, 2007.     

Structure and phase transformations in an elinvar alloy after various regimes of heat treatment

The microstructure, phase composition, and mechanical properties of the alloy 44NKhTYu have been studied using metallography, X-ray diffraction, and acoustic testing. The main peculiarities of the formation of intermetallic phases and their effect on the mechanical properties of the alloy have been determined.     

Fabrication of TiAl intermetallic phases by heat treatment of warm sprayed metal precursors

Warm Spraying is an atmospheric coating process based on high-velocity impact bonding of powder particles. By decreasing the temperature of combustion gas via mixing with nitrogen the oxidation of feedstock powder can be effectively controlled. This is particularly important for Ti-based coating materials, which rapidly oxidize at elevated temperatures.In this study, Ti–Al composite coatings were fabricated by the Warm Spray process using a mixture of titanium and aluminum powders as a feedstock and applying a two-stage heat treatment at 600 and 1000 °C to obtain intermetallic phases. The microstructure, chemical and phase composition of the deposited and heat-treated coatings were investigated using SEM, EDS and XRD. The experimental results show that TiAl₃ was the first intermetallic phase formed during the first-stage heat treatment. The growth of TiAl₃ layer occurred mainly by diffusion of Al into Ti particles. Significant porosity that developed during the heat treatment was caused mainly by Kirkendall effect. After the second-stage heat treatment, a coating layer with TiAl as the dominant phase was obtained with about 20 vol % porosity.     

Structure and properties of powder white iron after plastic deformation

Conclusions  

绿色低碳热处理标准体系构建

围绕国际和国内应对气候变化出台的一系列政策措施,介绍了“温室气体”、“碳达峰”、“碳中和”和“碳交易”等概念,讨论了热处理碳排放来源和核算方法。按照《国家标准化发展纲要》和《2030年前碳达峰行动方案》的工作思路,提出从碳排放核算、管理及评价,热处理节能与能源管理,绿色低碳热处理,热处理质量与生产效率4个方面构建绿色低碳热处理标准体系,并将其作为“十四五”热处理标准化工作的重点,从而为支撑和引领热处理行业绿色低碳发展打下坚实的基础。