Crystallization Kinetics of Hypo, Hyper and Eutectic Ni–Nb Glassy Alloys

Metals

Emilio Orgaz¹  Octavio Lozada²  José Manuel Hernández³  Ignacio Alejandro Figueroa³  José Gonzalo González³  Laura Esmeralda Mendoza³ 

[1] Departamento de Física y Química Teórica, Facultad de Química, Universidad Nacional Autónoma de México (UNAM), Circuito Exterior s/n, Cd. Universitaria, Ciudad de México 04510, Mexico;Facultad de Ingeniería, Universidad Panamericana, Augusto Rodin 498, Ciudad de México 03920, Mexico;Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México (UNAM), Circuito Exterior s/n, Cd. Universitaria, Ciudad de México 04510, Mexico;

关键词: Ni–Nb;    thermal behavior;    activation energy;    crystallization kinetics;    ribbon thicknesses;   

DOI  :  10.3390/met12050808

来源: DOAJ

【 摘 要 】

This study presents the thermal and kinetic behavior of Ni_58.5Nb_41.5, Ni_59.5Nb_40.5, and Ni_60.5Nb_39.5 binary glassy alloys. The alloys ingots were obtained through an electric arc furnace and the ribbons using the melt-spinning technique at two different wheel speeds, 8 and 25 m/s. The non-isothermal study was carried out by means of Differential Scanning Calorimetry (DSC) at five different heating rates: 12.5, 15, 17.5, 20, and 22.5 K/min. X-ray Diffraction (XRD) analysis showed a fully glassy phase for all ribbons for all compositions. For both wheel speeds, the ribbons with higher Nb content were significantly thinner than those with less content. The activation energies were calculated from the Kissinger method, showing the tendency E_p1>E_x1>E_g, where E_p1, E_x and E_g denote the activation energies of first peak temperature, the first crystallization onset and glass transition, respectively. The Flynn–Wall–Ozawa model displayed a close correlation with heating rates, ribbon thicknesses, and composition. The Nb content enhanced the glassy stability since the activation energy required for crystallization increased at higher Nb concentrations.

【 授权许可】

Unknown