Effect of growth rate on the microstructure and mechanical behavior of directionally solidified Y3Al5O12/MgAl2O4 eutectics

Abali S.

JOURNAL OF CRYSTAL GROWTH, vol.391, pp.18-24, 2014 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 391
  • Publication Date: 2014
  • Doi Number: 10.1016/j.jcrysgro.2013.12.050
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.18-24
  • Keywords: Directional solidification, Eutectics, Floating zone technique, Yttrium aluminum garnet, Magnesium aluminate spinel, HIGH-STRENGTH, PRECIPITATION, DEFORMATION, COMPOSITE, SAPPHIRE, KNOOP, CREEP
  • Çanakkale Onsekiz Mart University Affiliated: Yes


The mechanical properties of YAG-spinel (Y3Al5O12/MgAl2O4) eutectic rods were studied as a function of the solidification rate. Eutectic rods were grown by a laser-heated floating zone method. YAG-spinel eutectic rods measuring 2 mm in diameter and 200 mm in length were grown at rates of 0.1-10 mm/min with a temperature gradient of approximately 1 x 104 [gm. The compressive creep strength of a crystal grown at a rate of 5 mm/min and a now rate of 1.2 mm/min at 1500 degrees C under a strain rate of 1.0 x 10(-4) was only 398 MPa, which is slightly higher than that of crystals grown under different conditions. The highest flexure strength of the Y3Al5O12/MgAl2O4 material at ambient temperature was obtained at a growth rate of 5 mm/min. The maximum hardness reached 16.7 GPa, and the room fracture toughness was 3.9 MPa M-1/2. The changes in the mechanical behavior and the microstructure of the material that occurred at different growth rates are briefly discussed. (C) 2014 Elsevier B.V. All rights reserved