Abstract: It is disclosed a method of detecting and quantifying subsurface defects (10) in an article (1) made of high strength non magnetisable materials after the use in a high temperature environment. A crack (8) or gap on a surface (7) of the article (1) is brazed and after the brazing operation the crack (8) or any remaining braze defect or subsurface crack (10) is detected and quantified by means of a multifrequency eddy current system.

Abstract: It is disclosed a method for fabricating, modifying or repairing of single crystal or directionally solidified articles. Two single crystal or directionally solidified prefabricated parts are joint by isothermally brazing using a brazing material. After that an epitaxial or non-epitaxial layer on the surface of the created article and of the braze joint is applied using a laser metal forming process.

Abstract: A gas turbine component consists of a superalloy base material with a single crystal structure and a protective MCrAlY-coating. The MCrAlY-coating the MCrAlY has a &ggr;/&bgr;-phase and single crystal structure, which is epitaxial with the base material.

Abstract: A gas turbine component consists of a superalloy base material with a single crystal structure and a protective MCrAlY-coating (6). The MCrAlY-coating (6) has a g/g′ single crystal structure, which is epitaxial with the base material. It has be determined the critical factors for the successful epitaxial and crack-free growth of the MCrAlY-coating (6).

Abstract: It is disclosed a method of depositing a MCrAlY-coating (6) on the surface (5) of a single crystal (SX) or directionally solidified (DS) article (1). In a first step the article (1) is coated only at a local area by an electroplated method. In a second step the deposited MCrAlY-coating in single crystal form epitaxial with the base material of the article.

Abstract: It is disclosed a method for fabricating, modifying or repairing of single crystal (SX) or directionally solidified (DS) articles (1). Two single crystal (SX) or directionally solidified (DS) prefabricated parts are joint by isothermally brazing using a brazing material. After that an epitaxial or non-epitaxial layer on the surface of the created article (1) and of the braze joint is applied using a laser metal forming process.

Abstract: It is disclosed a method of determining the exposure temperature of Al and Cr of a &ggr;/&ggr;′ MCrAlY-coating after the use in a high temperature environment, the &ggr;/&ggr;′ MCrAlY-coating (6) exhibiting a non-equilibrium &ggr;/&ggr;′-microstructure at a temperature lower than the temperature during operation and the depletion of chromium from the &ggr;/&ggr;′-MCrAlY-coating (6) still allows the &agr;-Cr phase to form. The coating conductivity and permeability by means of a multifrequency eddy current system is measured at different locations of the component and from the measured conductivity and permeability the exposure temperature of said different locations of the components is determined.

Abstract: It is disclosed a method of detecting and quantifying subsurface defects (10) in an article (1) made of high strength non magnetisable materials after the use in a high temperature environment. A crack (8) or gap on a surface (7) of the article (1) is brazed and after the brazing operation the crack (8) or any remaining braze defect or subsurface crack (10) is detected and quantified by means of a multifrequency eddy current system.

Abstract: It is disclosed a method of measuring the thickness and/or the depletion of Al and Cr of a &ggr;/&ggr;′ MCrAlY-coating after the use in a high temperature environment, the &ggr;/&ggr;′ MCrAlY-coating (6) exhibiting a non-equilibrium &ggr;/&ggr;′-microstructure at a temperature lower than the temperature during operation. Before the coating (6) conductivity by means of a multifrequency eddy current system is measured a heat treatment is applied to transform the non-equilibrium &ggr;/&ggr;′-microstructure to a equilibrium microstructure having a &agr;-Cr phase. Subsequently the Al and/or Cr depletion of the coating (6) from the coating conductivity and permeability is determined.

Abstract: A method of depositing a layer (6) of highly oxidation and fatigue resistant MCrAlY-coating by an electroplated process has been described. A relative thin coating on an industrial gas turbine component was applied with a thickness control of ±20 &mgr;m of the thickness of the applied layer (6) on gas turbine articles (1). The said MCrAlY coatings comprise an addition of (wt.-%) 0.01 to 3% Fe. In addition to Fe the MCrAlY coatings may contain 0.5-2.5% Si, 0-1.5% Hf, 0.01-0.2% Zr and 0-2% Ta, alone or in combination.

Abstract: In a heat treatment process for a single-crystal or directionally solidified material body comprising a nickel-based superalloy, the material body is solution-annealed and then at a first temperature &ggr;′ particles of greater than 1 &mgr;m are precipitated in a proportion by volume with Vtot−V1 of less than 50%, where Vtot is the total amount of &ggr;′ particles after complete heat treatment and V1 is the proportion of the &ggr;′ particles which is greater than 1 &mgr;m, and at least at a second temperature ‘&ggr;’ particles of less than 1 &mgr;m are precipitated. The &ggr;′ particles are preferably precipitated in a size of 2 pin or more with a proportion by volume of 0.25<(Vtot−V1)/(100−V1)<0.55 at the first temperature. The proportion by volume Vtot of the &ggr;′ particles will be at least 50%.

Abstract: A process of brazing cracks and gaps in a single crystal article which takes places isothermally under the following conditions: the temperature of the isothermal solidification is between TLiqidus, Braze+5*(wt-%BBraze) and (Tsolidus, base material−70*(wt-%BBraze)), while (wt-%B*wt-%Cr) is between 15 and 40 and (Tsolv.&ggr;′, base material−TLiqidus, Braze) is above 140° C. This results in an homogeneous &ggr;/&ggr;′-microstructure of the isothermal solidified, brazed joint with mechanical properties similar to those of the base material.

Abstract: A process of brazing cracks and gaps in a single crystal article which takes places isothermally under the following conditions: the temperature of the isothermal solidification is between TLiqidus, Braze+5*(wt-%BBraze) and (Tsolidus, base material−70*(wt-%BBraze)), while (wt-% B*wt-%Cr) is between 15 and 40 and (Tsolv.&ggr;′, base material−TLiqidus, Braze) is above 140° C. This results in an homogeneous &ggr;/&ggr;′-microstructure of the isothermal solidified, brazed joint with mechanical properties similar to those of the base material.