Non-Hall-Petch hardness dependence in ultrafine fibrous MgAl 2 O 4 -MgO eutectic ceramics fabricated by the laser-heated floating zone (LFZ) method

Moshtaghion, B.M. (Universidad de Zaragoza) ; Peña, J.I. (Universidad de Zaragoza)

Resumen: MgAl 2 O 4 -MgO eutectic ceramics were fabricated by the laser-heated floating zone (LFZ) method with various growth rates to assess its possible beneficial effect on microstructural aspects and mechanical properties. It was determined that the growth rate optimizing the microstructure and mechanical properties is 750 mm/h; below this value, coarsening of the fibrous microstructure takes place with a degradation of these properties. In the extreme case of 50 mm/h growth rate, the presence of undesirable transverse cracks was unavoidable. Thanks to the high growth rate of 750 mm/h, ultra-fine fibrous microstructure MgAl 2 O 4 -MgO eutectic ceramics can thus be fabricated with greater hardness (15.5 GPa from Vickers indentation and 22 GPa from nanoindentation) and flexural strength (˜345 MPa). It is reported that hardness scales with the interfiber spacing ¿ according to a law of the type ln¿/¿, contrary to the assumed Hall-Petch-like dependence. This proposed law can be explained in terms of dislocation hardening induced by the MgO fibers.

Idioma: Inglés

DOI: 10.1016/j.jeurceramsoc.2019.04.015

Año: 2019

Publicado en: Journal of the European Ceramic Society 39 (2019), 3208-3212
ISSN: 0955-2219

Factor impacto JCR: 4.495 (2019)

Categ. JCR: MATERIALS SCIENCE, CERAMICS rank: 1 / 28 = 0.036 (2019) - Q1 - T1

Factor impacto SCIMAGO: 1.164 - Materials Chemistry (Q1) - Ceramics and Composites (Q1)

Financiación: info:eu-repo/grantAgreement/ES/MINECO-FEDER/MAT2016-77769R
Financiación: info:eu-repo/grantAgreement/ES/MINECO/Juan de la Cierva Program

Tipo y forma: Article (PostPrint)

Área (Departamento): Área Cienc.Mater. Ingen.Metal. (Dpto. Ciencia Tecnol.Mater.Fl.)