VIDAL CRESPO , Antonio

La producción de materiales en los últimos años ha cobrado gran importancia en el campo de la ciencia. Por ello se han desarrollado múltiples técnicas que permiten obtener materiales metaestables con propiedades superiores a los que se obtienen por técnicas convencionales. Una de estas técnicas es el aleado mecánico en molinos planetarios de...

Production of the intermetallic MnCo0.8Fe0.2Ge phase, interesting as magnetocaloric material, is obtained by using an almost fully amorphous mechanically alloyed precursor. Thermal treatment to develop the intermetallic phase has been reduced in time (from several hours or even days to few minutes), and temperature (from 1123 K to 723 K)....

Mechanical alloying using a planetary ball mill allowed us to obtain two homogeneous systems formed by units with nanometer size and MnCo0.8Fe0.2Ge1−xSix stoichiometry (x = 0 and 0.5). The phase evolution of the systems with the milling time was analyzed using X-ray diffraction. Thermal stability of the final products was studied using...

Mechanically amorphized MnCo1−xFexGe alloys (x = 0.20, 0.06 and 0.03) were used as precursors to obtain hexagonal austenite single phase samples. Combining thermomagnetic and magnetocaloric analysis and in situ X-ray diffraction, we observed that the presence of a distribution of transition temperatures jeopardizes the first order character of...

Various stability criteria developed for high-entropy alloys are applied to compositions produced by mechanical alloying. While they agree with the annealed samples, these criteria fail to describe the as-milled metastable systems, highlighting the ability of mechanical alloying to overcome the limitations imposed by these criteria. The...

Ni55Fe19Ga26 ribbons obtained by melt-spinning technique exhibit a martensitic transformation from L21 cubic austenite phase to 14 M martensite phase above room temperature. We have taken advantage of the existence of thermal hysteresis of the martensitic phase transition (~ 11 K) to analyze the effect of isothermal treatments on the reverse...

An almost single phase 14 M modulated martensite is obtained in melt spun ribbon of Ni55Fe17Ga26Co2 Heusler alloy. The effect of thermal treatments on the stability of the reverse martensitic transformation from 14 M modulated martensite to austenite phase in this system has been investigated by both non-isothermal and isothermal treatments....

The presence of a distribution of transition temperatures (DTT) is ubiquitous in materials science. It is common to ascribe deviations from theoretical pure-phase behavior to this fact. To adapt the different pure phase models to systems with a DTT, the parameters of such distribution must be known or at least estimated. In this review, the...