Details

Autor(en) / Beteiligte

• Bourban, S
• Karapatis, N
• Hofmann, H
• Kurz, W

Titel

Solidification microstructure of laser remelted Al sub 2 O sub 3 -ZrO sub 2 eutectic

Ist Teil von

• Acta materialia, 1997-12, Vol.45 (12), p.5069-5075

Erscheinungsjahr

1997

Quelle

ScienceDirect

Beschreibungen/Notizen

• Surface resolidification experiments using a high power CO sub 2 -laser have been performed on an Al sub 2 O sub 3 -ZrO sub 3 containing 36.8 at.% ZrO sub 2 eutectic alloy at beam velocities between 0.3 and 8 mmmults exp -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 exp 2 V was found to be approx9.6mult10 exp -17 m exp 3 mults exp -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 excpet the diffusion coefficient to be of the right order of magntiude or to have a negligible influence, agreement is found when using a larger liquid diffusion coefficient, D sub L approx5.10 exp -10 m exp 2 mults exp -1 .