METHOD FOR PRODUCING A COMPONENT FROM A GRADED TiAl ALLOY AND COMPONENT PRODUCED THEREFROM

Abstract

A method for producing a component from a TiAl alloy and a correspondingly produced component includes defining at least one first component region with a first property profile, and at least one second component region with a second property profile, which is different from the first property profile; providing a powder made of the TiAl alloy; additively manufacturing the component from the powder composed of the TiAl alloy, wherein the powder made of the TiAl alloy is melted for the cohesive binding of the powder particles to one another and to the substrate or to an already produced part of the component, and wherein the powder particles are melted for the formation of the first component region, and the powder particles for the formation of the second component region are melted under different conditions, so different chemical compositions of the deposited material are produced in both component regions.

1 . A method for producing a component from a TiAl alloy, comprising the following steps:
 defining at least one first component region having a first property profile, and at least one second component region having a second property profile, which is different from the first property profile;   providing a powder composed of the TiAl alloy;   additively manufacturing the component from the powder made of the TiAl alloy, wherein the powder made of the TiAl alloy is melted for the cohesive binding of the powder particles to one another and to the substrate or to an already produced part of the component, and wherein the powder particles are melted for the formation of the first component region and the powder particles for the formation of the second component region are melted under different conditions in such a way that different chemical compositions of the deposited material are produced in the first component region and in the second component region.   
     
     
         2 . The method according to  claim 1 , wherein the different conditions for melting the powder include different melting temperatures and/or different holding times in the molten state, and/or different surrounding pressures. 
     
     
         3 . The method according to  claim 1 , wherein the different conditions for melting the powder are selected so that different quantities of aluminum are vaporized. 
     
     
         4 . The method according to  claim 1 , wherein the different conditions for melting the powder during the production of the first and/or the second component region are varied over the corresponding first and/or second component region to such an extent that a material gradient is deposited in the corresponding first and/or second component region. 
     
     
         5 . The method according to  claim 1 , wherein the property profile in the first component region has a greater ductility than in the second component region, and/or in that the property profile in the second component region has a greater creep resistance than in the first component region. 
     
     
         6 . The method according to  claim 1 , wherein during the melting of the powder, 0 to 1 at. % Al is vaporized in the first component region and/or 2 to 4 at. % Al are vaporized in the second component region. 
     
     
         7 . The method according to  claim 1 , wherein a third or additional component regions are defined that have different property profiles than the first and/or second component regions. 
     
     
         8 . The method according to  claim 1 , wherein the first and/or second component regions are formed so that they have transition regions at their boundaries, in which the property profiles and/or the chemical compositions, and/or the microstructure are adjusted stepwise or continuously to the surrounding regions. 
     
     
         9 . The method according to  claim 1 , wherein the additive manufacture comprises selective laser beam melting, selective electron beam melting, and build-up welding. 
     
     
         10 . The method according to  claim 1 , wherein the TiAl powder provided for the additive manufacture is composed of an alloy that contains 45.5 to 48 at. % Al, 4 to 6 at. % Nb, and in total up to 2 at. % of the alloying elements Mo, W, Zr, Si, C and B, and the remainder of Ti along with unavoidable contaminants, and in that, after the additive processing, the component produced has first component regions that contain a maximum 44.5 to 48 at. % Al, 4 to 6 at. % Nb, and in total up to 2 at. % of the alloying elements Mo, W, Zr, Si, C and B, and the remainder of Ti along with unavoidable contaminants, and second component regions that contain a minimum of 43.5 to 46 at. % Al, 4 to 6 at. % Nb, and in total up to 2 at. % of the alloying elements Mo, W, Zr, Si, C and B, and the remainder of Ti along with unavoidable contaminants. 
     
     
         11 . The method according to  claim 1 , wherein after the additive manufacture, the component is subjected to a heat treatment, in particular a heat treatment that comprises at least two different annealing treatments, namely a solution annealing in the range of the solution temperature for γ-TiAl and an aging treatment at 800 to 950° C. for 2 to 6 hours with oven cooling. 
     
     
         12 . The method according to  claim 11 , wherein the solution annealing is carried out by hot isostatic pressing of the component, and/or in that the solution annealing is carried out at a temperature of 50 to 20° C. below the solution temperature of the γ-TiAl of the first component region or the component region with the highest Al concentration. 
     
     
         13 . The method of  claim 1 , wherein a component of a turbomachine made of a TiAl alloy is produced and is fabricated in one piece by additive manufacture, wherein the component comprises at least one first component region that has a first property profile, and at least one second component region that has a second property profile, which is different from the first property profile, wherein first and second component regions have different chemical compositions and different microstructures. 
     
     
         14 . The method according to  claim 13 , wherein the component is a blade and the first component region is an edge region of the blade, and the second component region is a core region of the blade, wherein the first component region has a greater ductility than the second component region and the second component region has a greater creep resistance than the first component region. 
     
     
         15 . The component according to  claim 13 , wherein the first component region has a structure containing greater than or equal to 30 vol. % globular γ-TiAl, and the second component region has a structure containing less than or equal to 1 vol. % globular γ-TiAl.