Properties of the Ti40Zr10Cu36Pd14 BMG modified by Sn and Nb aqdditions

The results of investigation of the influence of additions of 2 and 3 at.% of Sn and simultaneously of Sn and 3 at.% Nb on microstructure and properties of the bulk metallic glasses of composition (Ti40Cu36−x Zr10Pd14Sn x )100−y Nb y are reported. It was found that the additions of Sn increased the temperatures of glass transition (T g), primary crystallization (T x ), melting, and liquidus as well as supercooled liquid range (ΔT) and glass forming ability (GFA). The nanohardness and elastic modulus decreased in alloys with 2 and 3 at.% Sn additions, revealing similar values. The 3 at.% Nb addition to the Sn-containing amorphous phase decreased as well all the T g, T x , T L, and T m temperatures as ΔT and GFA; however, relatively larger values of this parameters in alloys containing larger Sn content were preserved. In difference to the previously published results, in the case of the amorphous alloys containing small Nb and Sn additions, a noticeable amount of the quenched-in crystalline phases was not confirmed, at least of the micrometric sizes. In the case of the alloys containing Sn or both Sn and Nb, two slightly different amorphous phase compositions were detected, suggesting separation in the liquid phase. Phase composition of the alloys determined after amorphous phase crystallization was similar for all compositions. The phases Cu8Zr3, CuTiZr, and Pd3Zr were mainly identified in the proportions dependent on the alloy compositions

Creation of wear-resistant near-surface-layers with inhomogeneous structure on NiTi alloy by ion implantation technology

In the present study we report the changes in the modified near-surface layer on NiTi shape memory alloy, caused by ion implantation as well as their influence on the structure and mechanical properties of this material. Experimental results of an inhomogeneous structure and tribological properties of implanted NiTi are discussed in this paper

Evolution of microstructure and residual stress during annealing of austenitic and ferritic steels

International audienceIn this work the recovery and recrystallization processes occurring in ferritic and austenitic steels were studied. To determine the evolution of residual stresses during material annealing the nonlinear sin 2 ψ diffraction method was used and an important relaxation of the macrostresses as well as the microstresses was found in the cold rolled samples subjected to heat treatment. Such relaxation occurs at the beginning of recovery, when any changes of microstructure cannot be detected using other experimental techniques. Stress evolution in the annealed steel samples was correlated with the progress of recovery process, which significantly depends on the value of stacking fault energy

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