A method comprising: removing a portion of a base component (12, 32, 62, 64, 92, 94) adjacent to a damaged portion of the base component (12, 32, 62, 64, 92, 94) to define a repair portion (14, 34) of the base component (12, 32, 62, 64, 92, 94), wherein the base component (12, 32, 62, 64, 92, 94) comprises a cobalt- or nickel-based superalloy, and wherein the repair portion (14, 34) of the base component (12, 32, 62, 64, 92, 94) comprises a through-hole (70, 98) extending from a first surface (22, 42) of the base component (12, 32, 62, 64, 92, 94) to a second surface (24, 44) of the base component (12, 32, 62, 64, 92, 94); forming a braze sintered preform (16, 36, 72, 100) to substantially reproduce a shape of the through-hole (70, 98), wherein the braze sintered preform (16, 36, 72, 100) comprises a Ni- or Co-based alloy; placing the braze sintered preform (16, 36, 72, 100) in the through-hole (70, 98); characterized by: positioning additional braze material (78, 80, 102) comprising the Ni- or Co-based alloy adjacent to the braze sintered preform (16, 36, 72, 100) to fill or cover parts of the repair portion (14, 34) or adjacent damage that the braze sintered preform (16, 36, 72, 100) does not fill, wherein: the additional braze material (78, 80, 102) comprises a second braze sintered preform (78, 80, 102), wherein the second braze sintered preform (78, 80, 102) comprises a sheet, and wherein the sheet overlies the braze sintered preform (16, 36, 72, 100) and at least part of the repair portion (14, 34) of the base component (12, 32, 62, 64, 92, 94); and heating at least the braze sintered preform (16, 36, 72, 100) and the additional braze material (78, 80, 102) to cause the braze sintered preform (16, 36, 72, 100) and the additional braze material (78, 80, 102) to join to the repair portion (14, 34) of the base component (12, 32, 62, 64, 92, 94) and change a microstructure of the braze sintered preform (16, 36, 72, 100) and the additional braze material (78, 80, 102) to a brazed and diffused microstructure. removing a portion of a base component (12, 32, 62, 64, 92, 94) adjacent to a damaged portion of the base component (12, 32, 62, 64, 92, 94) to define a repair portion (14, 34) of the base component (12, 32, 62, 64, 92, 94), wherein the base component (12, 32, 62, 64, 92, 94) comprises a cobalt- or nickel-based superalloy, and wherein the repair portion (14, 34) of the base component (12, 32, 62, 64, 92, 94) comprises a through-hole (70, 98) extending from a first surface (22, 42) of the base component (12, 32, 62, 64, 92, 94) to a second surface (24, 44) of the base component (12, 32, 62, 64, 92, 94); forming a braze sintered preform (16, 36, 72, 100) to substantially reproduce a shape of the through-hole (70, 98), wherein the braze sintered preform (16, 36, 72, 100) comprises a Ni- or Co-based alloy; placing the braze sintered preform (16, 36, 72, 100) in the through-hole (70, 98); characterized by: positioning additional braze material (78, 80, 102) comprising the Ni- or Co-based alloy adjacent to the braze sintered preform (16, 36, 72, 100) to fill or cover parts of the repair portion (14, 34) or adjacent damage that the braze sintered preform (16, 36, 72, 100) does not fill, wherein: the additional braze material (78, 80, 102) comprises a second braze sintered preform (78, 80, 102), wherein the second braze sintered preform (78, 80, 102) comprises a sheet, and wherein the sheet overlies the braze sintered preform (16, 36, 72, 100) and at least part of the repair portion (14, 34) of the base component (12, 32, 62, 64, 92, 94); and heating at least the braze sintered preform (16, 36, 72, 100) and the additional braze material (78, 80, 102) to cause the braze sintered preform (16, 36, 72, 100) and the additional braze material (78, 80, 102) to join to the repair portion (14, 34) of the base component (12, 32, 62, 64, 92, 94) and change a microstructure of the braze sintered preform (16, 36, 72, 100) and the additional braze material (78, 80, 102) to a brazed and diffused microstructure. positioning additional braze material (78, 80, 102) comprising the Ni- or Co-based alloy adjacent to the braze sintered preform (16, 36, 72, 100) to fill or cover parts of the repair portion (14, 34) or adjacent damage that the braze sintered preform (16, 36, 72, 100) does not fill, wherein: the additional braze material (78, 80, 102) comprises a second braze sintered preform (78, 80, 102), wherein the second braze sintered preform (78, 80, 102) comprises a sheet, and wherein the sheet overlies the braze sintered preform (16, 36, 72, 100) and at least part of the repair portion (14, 34) of the base component (12, 32, 62, 64, 92, 94); and heating at least the braze sintered preform (16, 36, 72, 100) and the additional braze material (78, 80, 102) to cause the braze sintered preform (16, 36, 72, 100) and the additional braze material (78, 80, 102) to join to the repair portion (14, 34) of the base component (12, 32, 62, 64, 92, 94) and change a microstructure of the braze sintered preform (16, 36, 72, 100) and the additional braze material (78, 80, 102) to a brazed and diffused microstructure.