Methods for repair of single crystal superalloys by laser welding and products thereof

A method for welding single crystal superalloys comprising the steps of:

• providing a substrate to be treated, said substrate comprising a single crystal superalloy;
• providing a filler, said filler comprising a superalloy;
• exposing said filler to a high power energy source to cause preheating and melting of said filler by said high power energy source;
• exposing a portion of a surface of said substrate to said high power energy source to cause partial melting of the portion of the surface of said substrate by said high power energy source;
• and
• depositing said filler onto the portion of the melted surface of said substrate to form a solid clad on said substrate to provide a superalloy weld.

A method for repairing a portion of a surface of a single crystal superalloy substrate comprising the steps of:

• providing a single crystal superalloy substrate having a surface defect;
• providing a superalloy filler;
• exposing said filler to a laser source to cause preheating and melting of said filler by said laser source;
• exposing a portion of a defective surface of said substrate to said laser source to cause melting of the portion of the defective surface of said substrate by said laser source;
• and
• depositing said filler onto the portion of the defective surface of said substrate to form a solid clad on the portion of the defective surface of said substrate to provide a superalloy repair of said surface defect of said substrate.

A method for coating the surface of a single crystal superalloy substrate comprising the steps of:

• selecting a portion of a surface of a single crystal superalloy substrate to be treated;
• providing an advanced superalloy filler;
• exposing said filler to a laser source to cause preheating and melting of said filler by said laser source;
• exposing the portion of the surface of said substrate to said laser source to cause melting of the portion of the surface of said substrate by said laser source;
• and depositing said filler to form a solid clad onto the portion of the surface of said substrate to provide a single crystal superalloy coating on the surface of said substrate.

A method for laser-welding a single crystal superalloy substrate comprising the steps of:

• providing a substrate comprising a single crystal superalloy selected from at least one of the group consisting of SC 180, RENÈ N5 and N6, CMSX-2, CMSX-4 and CMSX-10, and PWA 1480 and 1484;
• providing said substrate comprises at least an element selected from the group consisting of Ni, Co, Cr, Mo, W, Ta, Al, Ti, Re, Nb, Hf, C and B;
• providing a filler, said filler selected from at least one of the group consisting of a powder and a wire, said filler comprising a superalloy selected from at least one of the group consisting of HS-188, HASTELLOY X, INCO 713, INCO 738, INCO 939, MAR-M247, RENÈ 80, C 101 and modified MCrAlY;
• said MCrAlY modified with at least an element selected from at least one of the group consisting of Pt, Pd, Re, Ta, Hf, Zr, Si, C and B;
• said M selected from at least one of the group consisting of Ni, Co and Fe or combination thereof;
• exposing said filler to a laser source to cause preheating and melting of said filler by said laser source, said laser source selected from at least one of the group consisting of carbon dioxide, Nd:YAG, diode and fiber lasers;
• providing said filler comprises elements selected from at least one of the group consisting of Ni, Co, Fe, Cr, W, Mo, Al, Si, Nb, Ti, Ta, Zr, Re, Hf, C, B, Y and La;
• said laser source having a power of about 50-1500 watts, said laser source including a laser beam defocused by about 0.04 to about 0.06 inches;
• exposing a portion of a surface of said substrate to the laser source to cause melting of the portion of the surface of said substrate;
• depositing said preheated and melted filler onto the portion of the melted surface of said substrate to form a laser-welded clad bead with epitaxial structure having a width of about 0.04 to about 0.06 inches on the portion of the surface of said substrate;
• said preheating and melting of said filler by said laser source being achieved by feeding said filler through a co-axial nozzle of said laser source;
• providing a powder feeder, said powder fed into said co-axial nozzle by said by said powder feeder at a rate of 1.5-10 grams per minute;
• shrouding said preheated and melted filler and the portion of the surface of said melted substrate with an inert gas selected from at least one of the group consisting of He and Ar;
• and
• causing rapid relative motion of a beam of said laser source at a speed of about 5-14 inches per minute to an adjacent portion of the surface of said melted substrate to provide an epitaxial laser-weld.