GROWTH TEMPERATURES IN AL-CUAL2 AND SN-CD EUTECTIC ALLOYS

Measurements of the interface undercooling-growth velocity relationship for Al-CuAl2 eutectic alloys solidified horizontally and for Sn-Cd eutectic alloys solidified horizontally and vertically are presented. All the measurements confirm the relationship ΔT =Kv 1/2. The value of K for Al-CuAl2 alloys is 12.8°C cm-1/2 s1/2 and 13.3°C cm-1/2 s1/2 for Sn-Cd alloys for both modes of solidification. These values are much greater than those measured by Moore and Elliott. Reasons for the discrepancy are discussed. The K value for Al-CuAl2 alloys is only slightly greater than a recent measurement by Tassa and Hunt. The present measurements fit the extremum condition of the Hunt and Jackson theory of eutectic growth. © 1978 American Society for Metals and The Metallurgical Society of AIME.