FORMATION OF STABLE AND METASTABLE ALUMINIDES IN Al‒Ti‒Zr (Nb) ALLOYS

In the present work, we investigated the conditions of stable and metastable aluminides formation at crystallization of Al‒Ti‒Zr(Nb) melts overheated at 50 to 400 K above liquidus temperature

Development of high-entropy eutectic alloys for structural applications

The systems AlCoFeNiTi, CoCuFeNiTi, AlCoCrFeNi are considered from the point of view of creating structural alloys with a eutectic structure

Modification of Silumins with Complex Additives of Cu with Zr AND Cu with Ti

The modifying ability of the experimental Al-Cu-Ti, Al-Cu-Zr master alloys on the industrial alloy Al-7%Si-0.45Mg (A396, Ak7h) was evaluated and compared with the commercial Al-Ti-B master alloy. Modification was carried out in a bucket with a melt mass of 60 kg

Al-Cu-Zr MODIFYING ADDITIONS FOR ALUMINUM ALLOYS

The effect of small additions of zirconium and copper on the grain refinement of the Ak7 alloy and its structural components is considered. Additives were introduced both in the form of an experimental Al-Cu-Zr complex ligature and Al-Cu and Al-Zr binary alloys

EFFECT OF TI AND ZR ADDITIONS ON THE STRUCTURE AND MECHANICAL PROPERTIES OF THE Al-4%Cu ALLOY

The effect of small Ti and Zr additions on the evolution of the macrostructure and me-chanical properties of the Al-4%Cu alloy after deformation and heat treatment has been stud-ied. The advantage of using complex additions (Ti+Zr) in restraining recrystallization pro-cesses of Al-Cu alloys is shown.Работа выполнена в рамках государственного задания ИМЕТ УрО РАН с использованием оборудования ЦКП «Урал-М»

MODIFICATION OF ALUMINUM-SILICON ALLOYS WITH SMALL ADDITIONS OF TRANSITION METALS

An estimation of the modifying ability of experimental Al-Ti-B, Al-Ti-C, Al-Ti-Y, Al-Ti-Cu master-alloys on Al-7Si, Al-12Si aluminum-silicon alloys was carried out

FORMATION OF Al-Y ALLOYS OF HYPOEUTECTIC COMPOSITION WITH SMALL ADDITIONS OF Sc AND Zr

The study was made of the effect of small additions of transitional additives and heat treatment on the structure and service properties of Al-Y hypoeutectic alloys

Влияние температуры на формирование стабильных и метастабильных алюминидных фаз в сплавах системы Al-Zr-Nb

The paper considers formation conditions for stable and metastable aluminides Aln(Zr1-xNbx) obtained in the crystallization of superheated Al—Zr—Nb melts. At the close zirconium content in the alloys of 0.23—0.25 at.%, the niobium content varied from 0.05 to 0.21 at.%. Alloys were prepared in a resistance furnace at 1230 °C in an argon atmosphere in graphite crucibles. Alloys were cast into a bronze mold where the cooling rate was estimated at 200 °C per second. The structural features, distribution pattern, morphology, the composition of the matrix, dendritic cells and aluminides, as well as the structural type of intermetallics in the investigated alloys were studied using scanning electron and optical microscopy, X-ray phase analysis, X-ray diffraction analysis, electron microprobe analysis including inductively coupled plasma atomic emission spectroscopy. It was shown that the growth forms of stable aluminides (D023 structural type) change from the faceted to dendritic one, and primary metastable aluminides (L12 structural type) begin to form during the Al—Zr—Nb melt overheating at 360—365 °C above the liquidus temperature. Only metastable aluminides with both polyhedral and dendritic growth forms are formed in the alloys when overheated by 390 —395 °C and higher. The near-peritectic niobium composition of the Al—Zr—Nb alloy (at the zirconium content more than seven times higher than the peritectic one) are crucial factors in the formation of a large fraction of metastable AlnZr aluminides having a cubic L12 structure. It was shown that, in accordance with isomorphism rules, Nb replaces Zr at equivalent positions of the crystal lattice of aluminides. The intensity of isomorphism of the Al4(Zr0.79Nb0.21) intermetallics formed increases with the increasing melt overheating temperature.Рассмотрены условия формирования стабильных и метастабильных алюминидов Aln(Zr1-x.Nbx), образующихся при кристаллизации перегретых расплавов системы Al— Zr—Nb. При близком содержании циркония в сплавах (0,23—0,25 ат.%) содержание ниобия изменялось от 0,05 до 0,21 ат.%. Сплавы готовили в печи сопротивления при температуре 1230 °С в атмосфере аргона в графитовых тиглях. Разливку сплавов проводили в бронзовую изложницу, скорость охлаждения в которой составляла примерно 200 град/с. Электронной сканирующей и оптической микроскопией, а также методами рентгенофазового, рентгеноструктурного и микрорентгеноспектрального анализов, в том числе атомно-эмиссионной спектрометрией с индуктивно связанной плазмой, изучены структурные особенности, характер распределения, морфология, состав матрицы, дендритных ячеек и алюминидов, а также структурный тип интерметаллидов в исследуемых сплавах. Показано, что при перегреве расплавов системы Al—Zr—Nb над температурой ликвидуса на 360—365 °C происходит смена форм роста стабильных алюминидов структурного типа D023 от гранной к дендритной и начинают формироваться метастабильные алюминидные фазы с кубической решеткой структурного типа L12. При перегреве на 390—395 °C и выше в сплавах образуются только метастабильные алюминиды, имеющие как полиэдрические, так и дендритные формы роста. Околоперитектический (по ниобию) состав сплава Al—Zr—Nb (при содержании циркония, более чем в 7 раз превышающем перитектическое) определяет формирование в нем большой доли метастабильных алюминидов AlnZr с кубической решеткой L12. Показано, что в соответствии с правилами изоморфизма Nb замещает Zr в эквивалентных позициях кристаллической решетки алюминидов. С увеличением температуры перегрева расплавов интенсивность изоморфизма в формирующихся интерметаллидах Al4(Zr0,79Nb0,21 ) возрастает

Influence of the magnetic field on the velocity of the ion component of the particle beam generated during a nanosecond vacuum dielectric flashover

Results of experimental investigations into the influence of the direction of magnetic field of 0. 06 T on the velocity of ion component of particle flux generated during anode surface flashover of dielectrics in vacuum with voltage pulses of 230 kV are presented. It is demonstrated that the magnetic field applied in the plane of the sample surface decelerates the ion particle beam generated by the discharge. If the [E × B] vector is collinear with the external normal to the sample surface, the beam is decelerated less than in the case of the opposite orientation of the magnetic field. © 2012 Springer Science+Business Media New York