Alpha + beta or beta TITANIUM ALLOY AND METHOD FOR PRODUCTION THEREOF

Abstract

A titanium alloy containing copper, which cannot be realized by a conventional method, is provided, having a composition in which copper is contained in titanium with no segregation, and having improved strength and hardness. In addition a method is also provided, in which the titanium alloy is produced at lower cost than in a conventional method. The α+β or β titanium alloy contains copper at 1 to 10 mass %, has a crystal phase of β and α phase or of β phase, is formed of crystal particles not more than 100 μm, and has a copper concentration per an arbitrary specified 1 mm 3 portion of the crystal phase at within ±40% compared to another arbitrary specified portion. The α+β or β titanium alloy is produced by mixing 1 to 10 mass % of copper powder and the remainder of titanium alloy powder and then pressing and forming while being heated. The method for production of the α+β or β titanium alloy has a step of mixing 1 to 10 mass % of copper powder and the remainder of titanium alloy powder and a step of pressing and forming the mixture while being heated.

1 . A method for production of α+β type titanium alloy, the method comprising steps of:
 titanium alloy powder is produced from raw titanium alloy, and the titanium alloy contains at least aluminum and vanadium and further contains at least one selected from molybdenum, iron, chromium, and tin, and 
 1 to 10 mass % of copper powder and the titanium alloy powder are pressed and formed while being heated so as to form a dense compact. 
 
     
     
         2 . The method for production of α+β type titanium alloy according to  claim 1 , wherein a temperature in the pressing and forming while being heated (Tw(° C.)) is in the following range:
   ( Td− 100° C.)< Tw <( Td+ 100° C.)
 
 Td(° C.) being β transformation temperature of the titanium alloy that is pressed and formed. 
 
     
     
         3 . The method for production of α+β type titanium alloy according to  claim 1 , wherein size of a crystal phase consisting particles not greater than 100 μm, and the copper concentration per 1 mm 3  of an arbitrary specified portion in the crystal phase is within ±40% compared to another arbitrary specified portion. 
     
     
         4 . The method for production of α+β type titanium alloy according to  claim 1 , wherein the titanium alloy comprises titanium, 9-10 mass % vanadium, 1.8-2 mass % iron, 2.7-3 mass % aluminum and 1-10 mass % copper. 
     
     
         5 . The method for production of α+β type titanium alloy according to  claim 1 , wherein the titanium alloy comprises titanium, 13.5-15 mass % vanadium, 2.7-3 mass % chromium, 2.7-3 mass % aluminum, 2.7-3 mass % tin and 1-10 mass % copper. 
     
     
         6 . The method for production of α+β type titanium alloy according to  claim 1 , wherein the titanium alloy comprises titanium, 4.1-4.5 mass % aluminum, 2.7-3 mass % vanadium, 1.8-2 mass % iron, 1.8-2 mass % molybdenum and 1-10 mass % copper. 
     
     
         7 . The method for production of α+β type titanium alloy according to  claim 1 , wherein the titanium alloy comprises titanium, 4.5-5 mass % aluminum, 4.5-5 mass % vanadium, 4.5-5 mass % molybdenum, 2.7-3 mass % chromium and 1-10 mass % copper. 
     
     
         8 . The method for production of α+β type titanium alloy according to  claim 1 , wherein the titanium alloy comprises titanium, 4.5-5 mass % aluminum, 3.6-4 mass % vanadium, 0.5-0.6 mass % molybdenum, 0.3-0.4 mass % iron and 1-10 mass % copper. 
     
     
         9 . The method for production of α+β type titanium alloy according to  claim 1 , wherein the copper concentration per 1 mm 3  of an arbitrary specified portion in the crystal phase is within ±10% compared to average concentration of the α+β type titanium alloy. 
     
     
         10 . The method for production of α+β type titanium alloy according to  claim 1 , wherein the copper contained in a range of 3 to 10 mass %.