The Influence of Mold Material on Cooling Curve, Solidification Parameters, and Micro-hardness of Al-6wt.%Si in Unidirectional Solidification

The influence of mold material on cooling curve, solidification parameters, and micro-hardness were investigated. Al-6wt.% Si in clay and stainless steel mold was directionally solidified using vertical Bridgman type furnace. The samples were heated up to 700°C at 1.9°C/s heat rate, held for 60 minutes, cooled, and withdrawn at 40 µm/s. The results show that the increasing of thermal conductivity by 72% affects cooling curve shape, solidification parameters, and micro-hardness. Furthermore, comparative evaluation of the exponent value of the function of micro-hardness to distance and micro-hardness to growth rate also have been made to proposed the range of exponent value for each mold material.