Structures of Cu-Based Glass Forming System Doped with Iron

The effects of iron additions on the structure of (Cu0.47Ti0.34Zr0.11Ni0.08)100−xFex (x = 0, 1.5, 3, 6) glass forming system are presented. The alloys were synthesized by arc melting of high purity elements and melt spun to form rapidly quenched ribbons. X-ray diffraction studies showed the amorphous structure of the base and Fe-containing alloys, confirmed by the presence of exothermic peaks on differential scanning calorimetry curves. Bulk samples in the form of rods (Φ3 × 55 mm) were cast using a suction casting unit attached to the arc melter. Structural investigations revealed partial crystallization of the base Cu47Ti34Zr11Ni8 alloy. Iron additions significantly decreased the glass forming ability of the alloy, leading to primary crystallization of dendrites

Study of Physical Properties of Ba(Ti 1−2x Fe x Nb x )O 3 Ceramics

Ba(T

Формирование неоднородной структуры в приповерхностных слоях NiTi в результате ионной имплантации

В работе представлены результаты исследования структуры и химического состава NiTi после имплантации ионами N⁺, N⁺ и Ni⁺. Предложена модель процессов, происходящих в приповерхностных слоях NiTi. Показано, что в приповерхностном слое формируется двойной слой, состоящий из частично аморфизированной микроструктуры, обогащенной Ti и Ni, под которым находится слой микрокристаллической структуры, обогащенный Ti.Представлені результати дослідження структури і хімічного складу NiTi після імплантації іонами N⁺, N⁺ і Ni⁺. Запропонована модель процесів, що відбуваються в приповерхневих шарах NiTi. Показано, що в приповерхневому шарі формується подвійний шар, який складається з частково-аморфізованої мікроструктури, збагаченої Ti і Ni, під яким знаходиться шар мікрокристалічної структури, збагачений Ti.In work results researches of structure and chemical composition of NiTi, are presented after implantation, N⁺ and Ni⁺ the ions of N⁺. The model of processes, what be going on in the near-surface layers of NiTi is offered. Showed that a double layer, consisting of partly amorphous microstructure, enriched Ti and Ni, is formed in a nearsurface layer, which a layer of microcrystalline structure is under, enriched Ti

Thermal induced structural and magnetic transformations in Fe_{73.5−x}Ce_{x=0,3,5,7}Si_{13.5}B_9Nb_3Cu_1 amorphous alloy

Structural and magnetic properties of amorphous and partly crystallized Fe_{73.5−x}Ce_{x=0,3,5,7}Si_{13.5}B_9Nb_3Cu_1 alloys, were analysed in the temperature ranging from RT to 800 °C with scanning calorimetry and magnetometry. The Fe(Si) and Fe(B) structures were identified and characterised with set of crystallization temperatures and activation energies. Also, Curie temperatures for amorphous and for crystalline structures were determined and analysed as functions of Ce content

Study on crystallization phenomenon and thermal stability of binary Ni–Nb amorphous alloy

In this paper, a ribbon of binary Ni–Nb amorphous alloy was prepared by the melt spinning technique. Glass transition and crystallization phenomenon of the alloy were investigated by differential scanning calorimetry. Thermal properties of the ribbon of binary Ni–Nb upon heating and cooling were analysed by DTA at a heating/ cooling rate of 0.5 K s-1 under the purified argon atmosphere. The thermal stability of Ni–Nb amorphous alloy was studied by using an X-ray diffractometer equipped with an in situ heating system. The structure and fracture morphology of the ribbons were examined by X-ray diffraction and scanning electron microscopy methods

The Microstructure and Martensitic Transformation in Ni-Al Alloys with Yttrium Addition

The microstructure and martensitic transformation in the Ni-36.3Al-0.4Y (in at.%) alloy were investigated after homogenisation and plastic deformation by hot upsetting at 1100°C. The alloy exhibited large, recrystallised grains of the Ni-Al β phase with spherical precipitates inside the grains and a thin layer of other phases located at the grain boundaries. The SEM and EDX analysis showed that both types of precipitates were composed of two intermetallic phases (NixAl1-x)Y5 with different Ni to Al ratio. No yttrium content has been detected in the matrix β phase, probably because of the low solubility limit which is 0.1 at.%. The martensitic transformation was studied by TEM and DSC calorimetry. In large grains of the recrystallised material the M8 temperature was measured to be -4°C and the transformation proceeded in the range of 60 deg. The M8 temperature was lower than expected from the ratio of Ni to Al. Aging 1 hour at 240°C did not influence the range of the transformation. The TEM study of the β phase revealed strong and regular contrast modulations, probably being premartensitic effects. Also a regular spaced network of dislocations lying in the same directions as the contrast modulations, both in matrix and martensite, was noticed. In foils 7R structure of martensite, internally twinned, was predominantly found. The alloy was very brittle

Structural Characterization of Rapidly Solidified Al71Ni24Fe5 Alloy

The influence of rapid solidification from the liquid state on the structure of Al71Ni24Fe5 alloy was studied. The samples were prepared by induction melting (ingots) and high pressure die casting into a copper mold (plates). The structure was examined by X-ray diffraction (XRD), light microscopy and high resolution transmission electron microscopy (HRTEM). The mechanism of crystallization was described on the basis of differential scanning calorimetry (DSC) heating and cooling curves, XRD patterns, isothermal section of Al-Ni-Fe alloys at 850°C and binary phase diagram of Al-Ni alloys. The fragmentation of the structure was observed for rapidly solidified alloy in a form of plates. Additionally, the presence of decagonal quasicrystalline phase D-Al70.83Fe9.83Ni19.34 was confirmed by phase analysis of XRD patterns, Fast Fourier Transform (FFT) and Inverse Fast Fourier Transform (IFFT) of transmission electron microscopy images. The metastable character of D-Al70.83Fe9.83Ni19.34 phase was observed because of the lack of thermal effects on the DSC curves. The article indicates the differences with other research works and bring up to date the knowledge about Al71Ni24Fe5 alloys produced by two different cooling rates

Tem Study of Recrystallization in Ultra-Fine Grain AA3104 Alloy Processed by High-Pressure Torsion

The effect of annealing on the microstructure and the texture development was investigated in a particle containing AA3104 aluminium alloy. The samples were processed at room temperature by high-pressure torsion (HPT) up to ten turns. The nucleation of new grains was analyzed by a transmission electron microscope equipped with a system for local orientation measurements and a heating holder