Method for the powder-metallurgical production of components from titanium or titanium alloys

Abstract

A method for the powder-metallurgical production of a component from titanium or a titanium alloy is disclosed. In this method, following the customary procedure, first a green part is formed by using metal powder formed from titanium or the titanium alloy and is densified and compacted in a subsequent sintering step. Metal powder of titanium or the titanium alloy with an average grain size of <25 μm is used for producing the green part and the sintering step is carried out at a sintering temperature of up to a maximum of 1100° C. for a sintering at a sintering duration of ≤5 hours in an atmosphere that is under a reduced pressure in comparison with normal pressure. These measures achieve the effect that the grain structure of the material obtained, and consequently also the material properties, can be selectively influenced.

1 . A method for the powder-metallurgical production of a component from titanium or a titanium alloy, wherein first, using metal powder from titanium or the titanium alloy, a green part is formed and the green part is densified and compacted in a subsequent sintering step, wherein for producing the green part, metal powder from titanium or titanium alloy with a mean grain size of <25 μm, measured using laser diffraction according to ASTM B822-10, is used and the sintering step is performed at a sintering temperature up to a maximum of 1100° C. in an atmosphere under a reduced pressure in comparison with normal pressure. 
     
     
         2 . The method according to  claim 1 , wherein the maximum grain size of the metal powder from titanium or the titanium alloy is <30 μm. 
     
     
         3 . The method according to  claim 1 , wherein the sintering step is performed under a vacuum with a pressure of ≤10 −3  mbar. 
     
     
         4 . The method according to  claim 1 , wherein the sintering step is performed in an inert gas atmosphere at a pressure of ≤300 mbar. 
     
     
         5 . The method according to  claim 1 , wherein for producing the green part, metal powder from titanium or the titanium alloy with a mean grain size of <20 μm is used. 
     
     
         6 . The method according to  claim 1 , wherein the sintering duration is ≤3.5 h. 
     
     
         7 . The method according to  claim 1 , wherein the sintering duration is at least 1 h. 
     
     
         8 . The method according to  claim 1 , wherein the sintering temperature is up to a maximum of 1050° C. 
     
     
         9 . The method according to  claim 1 , wherein the sintering temperature amounts to at least 860° C. 
     
     
         10 . The method according to  claim 1 , wherein in the sintering step, the sintering temperature is adjusted in the range below a p-transition temperature of the titanium or titanium alloy material. 
     
     
         11 . The method according to  claim 1 , wherein the component after the sintering step has a material density of >97%. 
     
     
         12 . The method according to  claim 1 , wherein in the sintering step, a sintering temperature of below 950° C. is selected and that to achieve a material density in the component of >97%, after the sintering step the component is exposed to an additional step with pressure and optionally a temperature. 
     
     
         13 . The method according to  claim 1 , wherein the component, following the sintering step, is subjected to a thermal aftertreatment. 
     
     
         14 . The method according to  claim 13 , wherein the thermal aftertreatment is conducted in the form of one or more of the following treatment procedures: hot isostatic pressing (HIP), quench, and uniform rapid quench (URQ). 
     
     
         15 . A component produced according to  claim 1  from titanium or a titanium alloy having a globular α-structure with a grain size of <30 μm. 
     
     
         16 . A component produced according to  claim 1  from titanium or a titanium alloy having a grain structure with globular α-structure with mean grain size of <30 μm and lamellar (α+β) grain structure with a mean primary β-phase grain size of <90 μm. 
     
     
         17 . A component produced according to  claim 1  from titanium or a titanium alloy having a lamellar (α+β) grain structure with a mean primary β-phase grain size of <120 μm. 
     
     
         18 . The method according to  claim 3 , wherein the sintering step is performed under a vacuum with a pressure of ≤ 10   −5  mbar. 
     
     
         19 . The method according to  claim 4 , wherein the sintering step is performed in an argon atmosphere. 
     
     
         20 . The method according to  claim 5 , wherein metal powder from titanium or the titanium alloy with a mean grain size of <10 μm is used. 
     
     
         21 . The method according to  claim 20 , wherein metal powder from titanium or the titanium alloy with a mean grain size of <5 μm is used. 
     
     
         22 . The method according to  claim 6 , wherein the sintering duration is ≤3 h. 
     
     
         23 . The method according to  claim 22 , wherein the sintering duration is ≤2.5 h. 
     
     
         24 . The method according to  claim 7 , wherein the sintering duration is at least ≤2 h. 
     
     
         25 . The method according to  claim 8 , wherein the sintering temperature is up to a maximum of 1000° C. 
     
     
         26 . The method according to  claim 25 , wherein the sintering temperature is up to a maximum of 950° C. 
     
     
         27 . The method according to  claim 11 , wherein the component after the sintering step has a material density of >98%. 
     
     
         28 . The method according to  claim 28 , wherein the component after the sintering step has a material density of ≥99%. 
     
     
         29 . The method according to  claim 12 , wherein the additional step with pressure comprises one of cold isostatic pressing (CIP) and hot isostatic pressing (HIP). 
     
     
         30 . The method according to  claim 1 , wherein the sintering step is performed for a sintering duration of ≤5 h.