STRUCTURAL PHASE STATE OF HEAT-RESISTANT CAST INTERMETALLID NICKEL-BASED ALLOYS DEPENDING ON THE THERMAL TREATMENT MODES

Доклад отражает экспериментальные исследования режимов термической обработки (ТО) монокристаллических заготовок с кристаллографической ориентацией (КГО) [111] литейных ренийсодержащих интерметаллидных никелевых сплавов нового поколения серии ВИН после термической обработки (ТО). Показано, что обработка при температурах Tпр– —°С - —°С повлияла на структурно-фазовое состояние и работоспособность исследуемых сплавов.The report reflects the experimental investigations of the thermal treatment regimes of single-crystal bars with crystallographic orientation (CGO) [111] foundry rhenium-containing intermetallic nickel alloys of the new generation of VIN series after heat treatment. It has been established that the treatment at temperatures close to Tsolv– —°С - —°С affected the structural-phase state and the operability of the alloys under study.Работа выполнена при поддержке гранта РФФИ № 16-38-00260 «Исследование закономерностей формирования структурно-фазового состояния жаропрочных литейных интерметаллидных сплавов на основе никеля после различных режимов термической обработки». Авторы выражают глубокую благодарность соавтору сплавов ВИН1 и ВИН4 О. А. Базылевой, канд. техн. наук, зам. начальника по науке лаборатории «Жаропрочные сплавы на основе никеля» ФГУП «ВИАМ»

Исследование влияния высокотемпературной термической обработки на фазовый и химический состав сплава ВКНА-1В

The paper dwells on the features of the chemical composition and structure of alloys based on Ni3Al. It examines the effect of heat treatment on the structure and phase parameters and on the short-term strength of the intermetallic VKNA-1B alloy.Smelting bar stock was made by technique of vacuum induction. A directional solidification method was used to provide heat treatment of samples on the UVNS-4 installation.The heat treatment was performed in the following modes: heating to a temperature of 1200, 1290, 1300 ° C, holding for 100, 4, 4 hours, respectively, furnace cooling to 800 ° C, then air-cooling. For heating was used the batch furnace VEBK S 400/100 with a maximum operating temperature of 1350 ° C. Samples were loaded in the furnace at 800 0C.The phase composition of the VKNA-1B alloy was examined through physicochemical analysis based on electrochemical insulating phases in different electrolytes. The composition and quantity of the isolated phases were determined by the results of X-ray and chemical analysis methods.To analyse the microstructure was used a scanning electron microscope JSM-840. In original cast state the VKNA-1B alloy has a cellular-dendritic structure. In the axes of the dendrites there is a γ'-phase (~ 75-80% vol.) surrounded by a viscous γ-phase in the form of thin layers; in the inter-dendritic regions there are large particles of γ'-phase. The increasing temperature of heat treatment comes with coarsening γ'-phase particles in inter-dendritic regions and, essentially, has no effect on the phase composition of the alloy. Results of mechanical tensile tests have shown that the alloy retains high strength values after long-term exposure and the increasing cell size of γ'-phase in the axes of the dendrites when raising the temperature leads to an increase in short-term strength of the alloy.Проведено исследование фазового и химического состава интерметаллидного сплава ВКНА-1В в исходном литом состоянии (вакуумная индукционная выплавка и вакуумный индукционный переплав) и после различных режимов высокотемпературной термической обработки. Определены пределы кратковременной прочности и текучести на образцах сплава ВКНА-1В и проведена корреляция значений механических свойств с фазово-химическим составом. Установлено, что высокотемпературная термообработка, изменяя соотношение γʹ/γ-фаз, практически не влияет на стабильность карбидной фазы, что и отражается на стабильности кратковременных свойств интерметаллидного сплава на основе соединения Ni3Al при комнатной температуре. DOI: 10.7463/aplts.0615.082965

Research of High-Heat Treatment Effect on Phase and Chemical Composition of the VKNA-1V Alloy

The paper dwells on the features of the chemical composition and structure of alloys based on Ni3Al. It examines the effect of heat treatment on the structure and phase parameters and on the short-term strength of the intermetallic VKNA-1B alloy.Smelting bar stock was made by technique of vacuum induction. A directional solidification method was used to provide heat treatment of samples on the UVNS-4 installation.The heat treatment was performed in the following modes: heating to a temperature of 1200, 1290, 1300 ° C, holding for 100, 4, 4 hours, respectively, furnace cooling to 800 ° C, then air-cooling. For heating was used the batch furnace VEBK S 400/100 with a maximum operating temperature of 1350 ° C. Samples were loaded in the furnace at 800 0C.The phase composition of the VKNA-1B alloy was examined through physicochemical analysis based on electrochemical insulating phases in different electrolytes. The composition and quantity of the isolated phases were determined by the results of X-ray and chemical analysis methods.To analyse the microstructure was used a scanning electron microscope JSM-840. In original cast state the VKNA-1B alloy has a cellular-dendritic structure. In the axes of the dendrites there is a γ'-phase (~ 75-80% vol.) surrounded by a viscous γ-phase in the form of thin layers; in the inter-dendritic regions there are large particles of γ'-phase. The increasing temperature of heat treatment comes with coarsening γ'-phase particles in inter-dendritic regions and, essentially, has no effect on the phase composition of the alloy. Results of mechanical tensile tests have shown that the alloy retains high strength values after long-term exposure and the increasing cell size of γ'-phase in the axes of the dendrites when raising the temperature leads to an increase in short-term strength of the alloy