| 摘要 |
The article is cast in predetermined crystallographic orientation in a mould having communicating starter, selector and article-forming cavities (48, 50 and 52, respectively). The mould is heated above the liquidus temperature of the metal or alloy and the molten metal or alloy is flowed into the above-mentioned cavities. Crystallisation is initiated in the starter cavity (48) using chill plate (42) with crystal growth in a preferential direction into the selector cavity (50) and then into the article-forming cavity (52). The improvement comprises inhibiting initiation of crystal formation and promotion of crystal growth in the preferential direction in the selector cavity (50) by providing thermal insulation (70) at least partially around the selector cavity (50). |
