Method for treating a porous article

1. A method of treating a porous work piece, comprising:

spreading successive layers of a metal powder and selectively consolidating the metal powder of each layer using an electron beam to form a work piece having surface porosity, wherein the work piece has a non-porous body portion on which the surface porosity is located;

infiltrating a liquid metallic alloy into the surface porosity;

solidifying the liquid metallic alloy to at least partially fill the surface porosity; and

diffusing at least one constituent of the liquid metallic alloy into the work piece such that there is a concentration gradient of that constituent in the work piece.

2. The method as recited in claim 1 , wherein the metal powder is selected from a group consisting of a titanium-aluminum alloy and a superalloy.

3. The method as recited in claim 1 , including isothermally solidifying the liquid metallic alloy.

4. The method as recited in claim 1 , wherein the metal powder is a titanium-aluminum alloy.

5. The method as recited in claim 1 , wherein the infiltrating of the liquid metallic alloy into the surface porosity includes submerging at least a portion of the work piece in the liquid metallic alloy.

6. The method as recited in claim 1 , wherein the infiltrating of the liquid metallic alloy into the surface porosity includes contacting the work piece with a foil that is made of the metallic alloy and then melting the foil.

7. A method of treating a porous work piece, comprising:

spreading successive layers of a metal powder and selectively consolidating the metal powder of each layer using an electron beam to form a work piece having surface porosity;

infiltrating a liquid metallic alloy into the surface porosity, wherein the liquid metallic alloy is a silver-aluminum alloy; and

solidifying the liquid metallic alloy to at least partially fill the surface porosity.

8. The method as recited in claim 7 , wherein the silver-aluminum alloy has a eutectic composition.

9. The method as recited in claim 7 , wherein the aluminum oxidizes after the solidifying to form an alumina passive layer on the work piece.

10. The method as recited in claim 9 , wherein the alumina is alpha alumina.