| US 7,449,063 B2 | ||
| Method and mould for casting articles with a pre-determined crystalline orientation | ||
| Neil J D'Souza, Derby (United Kingdom); Philip A Jennings, Bristol (United Kingdom); and Keerthi Devendra, Derby (United Kingdom) | ||
| Assigned to Rolls-Royce plc, London (United Kingdom) | ||
| Filed on Nov. 20, 2006, as Appl. No. 11/601,718. | ||
| Claims priority of application No. 0524473.6 (GB), filed on Dec. 01, 2005. | ||
| Prior Publication US 2007/0125299 A1, Jun. 07, 2007 | ||
| Int. Cl. C30B 25/12 (2006.01) | ||
| U.S. Cl. 117—81 [117/83; 164/122.2; 164/122.1] | 4 Claims |
| 1. A method of forming an article having a pre-determined crystalline orientation comprising;
(a) determining a value for solidification length LS for a particular diameter R of a seed crystal when a maximum ingress
distance d of axial grain growth into an off-axial single crystal matrix is given by the relationship d=R;
(b) adjusting heat transfer across the seed melt and choosing a length for the seed to ensure maximum melt back length LM
following mould soak and molten liquid pour is given by the relationship LM is less than LS;
(c) determining an optimum channel diameter r for a channel between the seed and a forming article in a mould body by the
relationship r=R/4, and;
(d) positioning the channel in a region where a primary off-axial development matrix direction forms a converging disposition
with a mould wall.
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