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


Abali S.

JOURNAL OF CRYSTAL GROWTH, cilt.391, ss.18-24, 2014 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 391
  • Basım Tarihi: 2014
  • Doi Numarası: 10.1016/j.jcrysgro.2013.12.050
  • Dergi Adı: JOURNAL OF CRYSTAL GROWTH
  • Sayfa Sayıları: ss.18-24

Özet

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