Solidification microstructure of laser remelted Al{sub 2}O{sub 3}-ZrO{sub 2} eutectic
- Swiss Federal Inst. of Tech., Lausanne (Switzerland). Dept. of Materials
Surface resolidification experiments using a high power CO{sub 2}-laser have been performed on an Al{sub 2}O{sub 3}-ZrO{sub 2} containing 36.8 at.% ZrO{sub 2} eutectic alloy at beam velocities between 0.3 and 8 mm {center_dot} s{sup {minus}1}. The local growth rate has been measured by observation of the orientation of the microstructure using scanning electron microscopy. In the whole range of velocities, the structure is essentially a regular lamellar eutectic and the value of the growth product {lambda}{sup 2}V was found to be {approx} 9.6 {center_dot} 10{sup {minus}17} m{sup 3} {center_dot} s{sup {minus}1}. The measured eutectic spacings were compared with Jackson and Hunt model. Using thermophysical properties from the literature, the measured spacings were more than four times larger than the calculated ones. Assuming all parameters of the growth relationship except the diffusion coefficient to be of the right order of magnitude or to have a negligible influence, agreement is found when using a larger liquid diffusion coefficient, D{sub L} {approx} 5 {center_dot} 10{sup {minus}10} m{sup 2} {center_dot} s{sup {minus}1}.
- OSTI ID:
- 599706
- Journal Information:
- Acta Materialia, Vol. 45, Issue 12; Other Information: PBD: Dec 1997
- Country of Publication:
- United States
- Language:
- English
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