Mg2SiO4-MgAl2O4 directionally solidified eutectics: Hardness dependence modelled through an array of screw dislocations

Moshtaghioun, B.M. (Universidad de Zaragoza) ; Gomez-Garcia, D. ; Peña, J.I. (Universidad de Zaragoza)

Resumen: Mg2SiO4-MgAl2O4 eutectic ceramics have been fabricated by means of the laser floating zone (LFZ) technique. The microstructure has revealed as an unusual one at lower growth rate, composed of broken lamellae of MgAl2O4 distributed randomly along one matrix, composed of Mg2SiO4. At higher growth rates, a cell structure with intra-cell lamella structure is dominant. Contrary to most eutectic systems, hardness is not dependent upon the inter-spacing, but it does depend on one characteristic length of lamellae: their perimeter. One simple model based upon the dislocation is proposed, which successfully accounts for such extraordinary hardness law. Accordingly, Mg2SiO4-MgAl2O4 eutectic ceramics fabricated at 50 mm/h growth rate with the smallest MgAl2O4 lamella perimeter favorably showed more elevated hardness (13.4 GPa from Vickers indentation and 15.3 GPa from nanoindentation) and strength (~430 MPa) than those found in the monolithic Mg2SiO4 matrix.

Idioma: Inglés

DOI: 10.1016/j.jeurceramsoc.2020.05.015

Año: 2020

Publicado en: Journal of the European Ceramic Society 40, 12 (2020), 4171-4176
ISSN: 0955-2219

Factor impacto JCR: 5.302 (2020)

Categ. JCR: MATERIALS SCIENCE, CERAMICS rank: 2 / 29 = 0.069 (2020) - Q1 - T1

Factor impacto SCIMAGO: 1.204 - Materials Chemistry (Q1) - Ceramics and Composites (Q1)

Financiación: info:eu-repo/grantAgreement/ES/DGA-FEDER/T02-17R
Financiación: info:eu-repo/grantAgreement/ES/MINECO-FEDER/MAT2015-71411-R
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.)