Sintering kinetics of Ni2FeSb powder alloys produced by mechanical milling
(1. Unidad Académica de Ingeniería I, Universidad Autónoma de Zacatecas,
Jardín Juárez 147 Centro Histórico, Zacatecas, Zacatecas, C. P. 98000, México;
2. Departamento de Ingeniería de Proyectos, CUCEI, Universidad de Guadalajara,
Blvd. Marcelino García Barragán 1421, Olímpica, Guadalajara, Jalisco, C. P. 44430, Mexico;
3. INICIT, Universidad Michoacana de San Nicolás de Hidalgo,
Fco. J. Mujica S/N, C.U., Morelia, Michoacán, C. P. 58060, México;
4. División de Estudios de Posgrado e Investigación, TecNM/Instituto Tecnológico de Morelia,
Av. Tecnológico # 1500, Colonia Lomas de Santiaguito, Morelia, Michoacán, C. P. 58120, México)
Jardín Juárez 147 Centro Histórico, Zacatecas, Zacatecas, C. P. 98000, México;
2. Departamento de Ingeniería de Proyectos, CUCEI, Universidad de Guadalajara,
Blvd. Marcelino García Barragán 1421, Olímpica, Guadalajara, Jalisco, C. P. 44430, Mexico;
3. INICIT, Universidad Michoacana de San Nicolás de Hidalgo,
Fco. J. Mujica S/N, C.U., Morelia, Michoacán, C. P. 58060, México;
4. División de Estudios de Posgrado e Investigación, TecNM/Instituto Tecnológico de Morelia,
Av. Tecnológico # 1500, Colonia Lomas de Santiaguito, Morelia, Michoacán, C. P. 58120, México)
Abstract: A ternary Ni2FeSb shape memory alloy was fabricated by powder metallurgy route. Sintering kinetics was estimated from dilatometry tests; whereas the microstructure and morphology of the powder and consolidated bulk samples were evaluated by XRD and SEM, respectively. Microhardness tests were performed on the surface of sintered samples. The results indicated that milling time has an effect on the shape and particle size as well as the homogeneity of the crystalline structures of the powders. Samples with longer milling time presented higher relative densities, better distribution of the elements on the alloy as well as the L21 and martensite phases, which will give the shape memory effect. The estimated activation energy values ranged from 109 to 282 kJ/mol at temperatures between 750 and 1273 K, indicating that sintering is controlled mainly by volume diffusion. Microhardness was improved by increasing the milling time and the heating rate.
Key words: Ni-based shape memory alloy; mechanical milling; solid state sintering; microhardness