Centrifugal casting method, centrifugal casting apparatus, and cast alloy produced by same

A centrifugal casting method, comprising the steps of melting a metal-containing material body through application of heat while rotating the material body;

• sprinkling the molten material by the effect of rotation;
• and causing the sprinkled molten material to be deposited and to solidify on an inner surface of a rotating cylindrical mold,
• an axis of rotation R of the metal-containing material body and an axis of rotation L of the cylindrical mold being caused not to run parallel to each other.

A rare-earth magnet alloy which is obtained through casting, characterized by containing one or more elements selected from among Nd, Pr, and Dy in a total amount of 11.0 at. % to 15.2 at. % and characterized in that, when determined in an as-cast state of the alloy, a microstructure containing a dendritic αFe phase occupies an area percentage of not greater than 10% as measured on a cross section of a cast product taken along a thickness direction and that the cast product assumes a thickness of 3 mm to 30 mm.

A rare-earth magnet alloy which is obtained through casting, characterized by containing one or more elements selected from among Nd, Pr, and Dy in a total amount of 11.0 at. % to 15.2 at. % and characterized in that, when determined in an as-cast state of the alloy, a microstructure containing dendritic αFe occupies an area percentage of not greater than 10% as measured on a cross section of a cast product taken along a thickness direction and that crystal grains having a diameter of not less than 1,000 μm as measured along a long axis occupy an area percentage of 10% to 98% as measured on the cross section.

An R-T-B-type rare-earth magnet alloy which is obtained through casting, characterized in that, when determined in an as-cast state of the alloy, a microstructure containing a dendritic αFe phase occupies an area percentage of not greater than 10% as measured on a cross section of a cast product taken along a thickness direction and that the cast product assumes a thickness of 3 mm to 30 mm.

An R-T-B-type rare-earth magnet alloy which is obtained through casting, characterized in that, when determined in an as-cast state of the alloy, a microstructure containing dendritic αFe occupies an area percentage of not greater than 10% as measured on a cross section of a cast product taken along a thickness direction and that crystal grains having a diameter of not less than 1,000 μm as measured along a long axis occupy an area percentage of 10% to 98% as measured on the cross section.

A rare-earth magnet alloy which is obtained through casting, characterized by containing one or more elements selected from among Nd, Pr, and Dy in a total amount of 11.0 at. % to 15.2 at. % and characterized in that, when determined in an as-cast state of the alloy, a dendritic αFe phase is substantially absent as observed on a cross section of a cast product taken along a thickness direction and that the cast product assumes a thickness of 3 mm to 30 mm.

A rare-earth magnet alloy which is obtained through casting, characterized by containing one or more elements selected from among Nd, Pr, and Dy in a total amount of 11.0 at. % to 15.2 at. % and characterized in that, when determined in an as-cast state of the alloy, a dendritic αFe is substantially absent as observed on a cross section of a cast product taken along a thickness direction;

• crystal grains having a diameter of not less than 1,000 μm as measured along a long axis occupy an area percentage of 50% to 98% as measured on the cross section;
• and the cast product assumes a thickness of 3 mm to 30 mm.

A rare-earth magnet alloy which is obtained through casting, characterized by containing one or more elements selected from among Nd, Pr, and Dy in a total amount of 11.0 at. % to 15.2 at. % and characterized in that, when determined in an as-cast state of the alloy, a dendritic αFe is substantially absent as observed on a cross section of a cast product taken along a thickness direction;

• as measured on the cross section, crystal grains having a diameter of not less than 1,000 μm as measured along a long axis occupy an area percentage of 50% to 98% and crystal grains assume an average diameter of not less than 60 μm as measured along a short axis;
• and the cast product assumes a thickness of 3 mm to 30 mm.