In-situ sintering reaction of Al2O3–LaAl11O18–ZrO2 composite

• Published in: International journal of refractory metals & hard materials Vol. 54; pp. 230 - 236
• Main Authors: Naga, S.M., Hassan, A.M., El-Maghraby, H.F., Awaad, M., Elsayed, Hamada
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-01-2016
• Subjects: Aluminum oxide; Densification; Hard materials; Hardness; In situ sintering reaction; Lanthanum hexaluminates; Mechanical properties; Microstructure; Origin of fracture; Particulate composites; Refractory metals; Sintering; Mechanical properties; In situ sintering reaction; Microstructure; Lanthanum hexaluminates; Origin of fracture
• ISSN: 0263-4368; 2213-3917
• DOI: 10.1016/j.ijrmhm.2015.07.026

Al2O3–LaAl11O18–ZrO2 composites were prepared by in situ sintering reaction of different proportions of Al2O3 and La2Zr2O7. The studied batches were uniaxially pressed and pressureless sintered at 1600°C up to 1725°C for 1h. Phase composition study reveals that the only present phases are alumina, lanthanum hexaluminates and zirconia. No other intermediate phases are present. Rodlike LaAl11O18 was observed in the sintered bodies containing more than 25wt.% LaAl11O18. The effect of rodlike particles on the densification and mechanical behavior was discussed. It was found that increasing the LaAl11O18 content more than 25wt.% enhances the fracture toughness, but reduces both the bending strength and the hardness of the sintered composites.
•In situ sintering reaction between Al2O3 and La2Zr2O7 was performed.•The effect of LaAl11O18 on the mechanical properties of LA6/Al/Zr composite was studied.•Formation of LaAl11O18 rodlike particles affects the densification and mechanical behavior of the composite.•Introduction of ZrO2 enhances the behavior of the composite.