A method comprising: removing a portion of a base component adjacent to a damaged portion of the base component to define a repair portion of the base component , wherein the base component comprises a cobalt- or nickel-based superalloy, and wherein the repair portion of the base component comprises a through-hole extending from a first surface of the base component to a second surface of the base component ; forming a braze sintered preform to substantially reproduce a shape of the through-hole , wherein the braze sintered preform comprises a Ni- or Co-based alloy; placing the braze sintered preform in the through-hole ; characterized by : positioning additional braze material comprising the Ni- or Co-based alloy adjacent to the braze sintered preform to fill or cover parts of the repair portion or adjacent damage that the braze sintered preform does not fill, wherein: the additional braze material comprises a second braze sintered preform , wherein the second braze sintered preform comprises a sheet, and wherein the sheet overlies the braze sintered preform and at least part of the repair portion of the base component ; and heating at least the braze sintered preform and the additional braze material to cause the braze sintered preform and the additional braze material to join to the repair portion of the base component and change a microstructure of the braze sintered preform and the additional braze material to a brazed and diffused microstructure. removing a portion of a base component adjacent to a damaged portion of the base component to define a repair portion of the base component , wherein the base component comprises a cobalt- or nickel-based superalloy, and wherein the repair portion of the base component comprises a through-hole extending from a first surface of the base component to a second surface of the base component ; forming a braze sintered preform to substantially reproduce a shape of the through-hole , wherein the braze sintered preform comprises a Ni- or Co-based alloy; placing the braze sintered preform in the through-hole ; characterized by : positioning additional braze material comprising the Ni- or Co-based alloy adjacent to the braze sintered preform to fill or cover parts of the repair portion or adjacent damage that the braze sintered preform does not fill, wherein: the additional braze material comprises a second braze sintered preform , wherein the second braze sintered preform comprises a sheet, and wherein the sheet overlies the braze sintered preform and at least part of the repair portion of the base component ; and heating at least the braze sintered preform and the additional braze material to cause the braze sintered preform and the additional braze material to join to the repair portion of the base component and change a microstructure of the braze sintered preform and the additional braze material to a brazed and diffused microstructure. positioning additional braze material comprising the Ni- or Co-based alloy adjacent to the braze sintered preform to fill or cover parts of the repair portion or adjacent damage that the braze sintered preform does not fill, wherein: the additional braze material comprises a second braze sintered preform , wherein the second braze sintered preform comprises a sheet, and wherein the sheet overlies the braze sintered preform and at least part of the repair portion of the base component ; and heating at least the braze sintered preform and the additional braze material to cause the braze sintered preform and the additional braze material to join to the repair portion of the base component and change a microstructure of the braze sintered preform and the additional braze material to a brazed and diffused microstructure. <EOS>