Phase transitions in crystals with a BCC structure

Kassan‐Ogly, F. A.; Архипов, В. Е.; Shestakov, Alexander

doi:10.1134/s0031918x10060025

Cited by 5 publications

(3 citation statements)

References 10 publications

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“…The conclusion on the formation of intermediate phases upon the so-called reconstructive phase transitions bcc-hcp and bcc-fcc resulted from the theoretical analysis of the transformations in the mode of cooperative thermal oscillations of the atomic planes [56]. In these cases intermediate phases take part in the subgroup relation between the symmetry groups of the phases above and below the transformation point.…”

Section: Resultsmentioning

confidence: 99%

Discovery of metastable tetragonal disordered phase upon phase transitions in the equiatomic nanostructured FePd alloy

et al. 2013

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Specific features of the phase transformation A1 ! L1 0 (space groups Fm3m and P4/mmm, respectively) in single crystals of the equiatomic alloy FePd subjected to annealings both in the absence and in the presence of external uniaxial load, as well as in polycrystalline samples that had undergone severe plastic deformation via high-pressure torsion and subsequent annealing, have been studied. An investigation of the single crystals in a nanostructured state formed at different stages of ordering annealing was performed using optical polarization, thermomagnetic and transmission electron microscopy (TEM) methods. The nanostructured state of the polycrystalline samples FePd after deformation of both disordered and ordered FePd alloys and subsequent annealing was examined with the help of TEM and X-ray techniques. The results obtained were analyzed based on the known concepts of the symmetry theory of phase transitions. It was concluded that the atomic ordering in the FePd alloys is preceded by the formation of a ferroelastic disordered bodycentered tetragonal phase with the structural type A6 and the space group I4/mmm. Experimental data that evidence the existence of a tetragonal disordered phase both in the single crystals and in the polycrystalline samples of FePd after severe plastic deformation and subsequent annealing are reported. Thus, the A1 M A6 M L1 0 phase transformation represents a combination of different types of phase transitions such as cooperative displacement A1 M A6 and ordering A6 M L1 0 of atoms.

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Section: Resultsmentioning

confidence: 99%

Discovery of metastable tetragonal disordered phase upon phase transitions in the equiatomic nanostructured FePd alloy

et al. 2013

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“…A 30h se observa que la máxima cantidad de fase TiTaSn-β, fue de un 79,80% en peso, predominando la transformación de fases αβ. Posteriormente, a las 50h se identificó un incremento de la fase TiTaSn-α y TiTaSn-γ, lo que muestra que ocurren las siguientes transformaciones reportadas en literatura, βα [44] y βγ [45]. Finalmente, a 100h, se observó un incremento en TiTaSn-β y TiTaSn-γ, indicando que ocurren las transformaciones αβ y αγ, inducida por las altas deformaciones causadas por el aleado mecánico [46,47].…”

Section: Resultsunclassified

“…Esa información es relevante para analizar , la posibilidad de la recristalización mecánica, y saber qué fase se está formando [41][42][43]. En todos los refinamientos se obtuvieron valores de bondad de ajuste (χ 2 ) y R wp inferiores a 2 y 10%, respectivamente, lo que muestra buena calidad del refinamiento [44,45]. En la Figura 4 se muestra un ejemplo del refinamiento de la muestra Ti-13Ta-3Sn (%at.)…”

Section: Resultsunclassified

Estudio de perfiles de difracción de rayos X de una aleación Ti-13Ta-3Sn obtenida por aleado mecánico

et al. 2020

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RESUMEN Las aleaciones Ti-β se han vuelto altamente demandadas en la industria, por sus buenas características físicas y químicas. En el presente trabajo, se sintetizó una aleación Ti-13Ta-3Sn (%at) por aleado mecánico con tiempos entre 2 y 100h. Las aleaciones se caracterizaron por difracción de rayos X (DRX) y los patrones se analizaron por el método Rietveld con el software MAUD. Se caracterizaron los cambios microestructurales y la evolución de las fases Ti-α y Ti-β. Se identificó la presencia una nueva fase metaestable fcc y la síntesis de una aleación con un 79,80% en peso de fase Ti-β, ambas con tamaño de cristalita nanométrico.

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