Method of hardening titanium and titanium alloys

Abstract

A method of hardening the outer surface of a titanium or titanium alloy substrate under standard atmospheric conditions. The method comprises focusing an electromagnetic beam from a laser generating apparatus, absent the disposition of a chemical compound, onto at least a portion of the substrate to heat it to a point below the melting point of the substrate. The treated substrate has a substantial increased harness and durability compared to an untreated surface of titanium or titanium alloy.

1 . A method of hardening an outer surface of a metallic substrate in open atmospheric conditions comprising the steps of:
 providing a substrate of titanium or titanium alloys;   focusing an electromagnetic radiation beam formed by a laser generating apparatus onto at least a portion of said substrate surface at sufficiently high power densities to cause an incandescent reaction above the substrate melting temperature with the substrate; and   limiting the incandescent reaction at any given area of the substrate to a sufficiently short period of time to prevent any substantial melting of the substrate, whereby said laser treated surface of said substrate has a substantial increased hardness and durability compared to an untreated surface of said substrate.   
   
   
       2 . The method as set forth in  claim 1 , wherein said laser generating apparatus is operated at a frequency between about 25 to about 50 kHz. 
   
   
       3 . The method as set forth in  claim 1 , wherein said laser generating apparatus operates at a power density of about 606,664 watts/mm 2 . 
   
   
       4 . The method as set forth in  claim 1 , wherein said laser generating apparatus operates at a scanning speed between about 0.01 to about 5.0 inches/sec. 
   
   
       5 . A method of hardening an outer surface of a metallic substrate in open atmospheric conditions consisting of the steps of:
 providing a substrate of titanium or titanium alloys;   focusing an electromagnetic radiation beam formed by a laser generating apparatus onto at least a portion of said substrate surface at sufficiently high power densities to cause an incandescent reaction above the substrate melting temperature with the substrate; and   limiting the incandescent reaction at any given area of the substrate to a sufficiently short period of time to prevent any substantial melting of the substrate, whereby said laser treated surface of said substrate has a substantial increased hardness and durability compared to an untreated surface of said substrate.   
   
   
       6 . The method as set forth in  claim 5 , wherein said laser generating apparatus is operated at a frequency between about 25 to about 50 kHz. 
   
   
       7 . The method as set forth in  claim 5 , wherein said laser generating apparatus operates at a power density of about 606,664 watts/mm 2 . 
   
   
       8 . The method as set forth in  claim 5 , wherein said laser generating apparatus operates at a scanning speed between about 0.01 to about 5.0 inches/sec. 
   
   
       9 . A titanium containing composition having a hardness in the range of 965 to 1200 Koops hardness number produced by the process of  claim 1 . 
   
   
       10 . A titanium containing composition having a hardness in the range of 965 to 1200 Koops hardness number produced by the process of  claim 5 .