Aluminum coated columbium base alloys

Claim 2

The article of claim 1 which consists essentially of columbium aluminide modified by 5 to 8 percent of Ti and up to 5 percent of V.

Claim 3

The article of claim 1 which consists essentially of columbium aluminide modified by from 5 to 9 percent of Ti and from 8 to 17 percent of Mo.

Claim 4

The article of claim 1 which consists essentially of columbium aluminide modified by 5 to 8 percent of Ti and up to 24 percent in the aggregate of Mo and Ta.

Claim 5

A composite article of manufacture having good resistance to oxidation at elevated temperatures and resistance to cyclic fatigue failure, which article comprises: A. a substrate having a composition by weight, selected from the group consisting of: a. at least 45 percent Cb, 15 to 35 percent Ti, and an effective modifying amount of at least one metal modifier selected from the group consisting of Cr, V, and Mo, the maximum content of each of said selected metal modifiers in the substrate being 13 percent of Cr, 6 percent of V, and 35 percent of Mo; and b. at least 35 percent Cb, 15 to 25 percent Ti, and an effective modifying amount of at least one metal modifier selected from the group consisting of Cr, V, and Mo-Ta, the maximum content of each of said selected metal modifiers in the substrate being 13 percent of Cr, 6 percent of V, and up to 40 percent in thE aggregate of Mo and Ta, the weight ratio of Mo to Ta being from about 1:2 to about 2:1; said substrate containing not more than about 25 percent in the aggregate of Ti, Cr, Mo, and Ta when at least 3 percent V is present in said substrate; and B. a thermal-cyclic-failure resistant, defect-resistant, and broad range oxidation-resistant coating superimposed on said substrate and forming a surface zone consisting essentially of columbium aluminide, predominantly in the trialuminide form, and modified by combinations of modifying elements, in amounts by weight of the coating, selected from the group consisting of: a. 5 to 10 percent of Ti, and an effective modifying amount of at least one metal modifier selected from the group consisting of Cr, V, and Mo, the maximum amount of each of said modifier being 7 percent of Cr, 5 percent of V, and 20 percent of Mo; and b. 5 to 8 percent of Ti and an effective modifying amount of at least one metal modifier selected from the group consisting of Cr, V, and Mo, the maximum amount of each of said metal modifiers being 7 percent of Cr, 5 percent of V, and up to 25 percent in the aggregate of Mo and Ta, the weight ratio of Mo to Ta being from about 1:2 to about 2:1; said coating containing not more than about 10 percent in the aggregate of Ti, Cr, Mo, and Ta when at least 2 percent V is present in said coating, the coating being modified by Ti and the selected metal modifier in amounts substantially proportionate by weight to the amounts of these elements, respectively, in the substrate.

Claim 6

The article of claim 6 wherein said substrate consists essentially of 20 to 35 percent Ti, up to 13 percent Cr, balance essentially Cb.

Claim 7

The article of claim 7 wherein said substrate consists essentially of 20 to 35 percent Ti, 6 to 13 percent Cr, and balance essentially Cb.

Claim 8

The article of claim 8 wherein said substrate consists essentially of about 25 percent Ti, about 6 percent Cr, and balance essentially Cb.

Claim 9

The article of claim 8 wherein said substrate consists essentially of about 25 percent Ti, about 13 percent Cr, and balance essentially Cb.

Claim 10

The article of claim 6 wherein said substrate consists essentially of 15 to 25 percent Ti, up to 6 percent V, and balance essentially Cb.

Claim 11

The article of claim 11 wherein said substrate consists essentially of about 25 percent Ti, about 6 percent V, and balance essentially Cb.

Claim 12

The article of claim 6 wherein said substrate consists essentially of 15 to 25 percent Ti, up to 13 percent Cr, up to 6 percent V, and balance essentially Cb, the aggregate Ti and Cr present not exceeding about 25 percent by weight of said substrate.

Claim 13

The article of claim 6 wherein said substrate consists essentially of 15 to 30 percent Ti, up to 35 percent Mo and at least 45 percent Cb.

Claim 14

The article of claim 14 wherein said substrate consists essentially of 15 to 30 percent Ti, 15 to 30 percent Mo, and at least 45 percent Cb.

Claim 15

The article of claim 15 wherein said substrate consists essentially of about 15 percent Ti, about 15 percent Mo, and balance essentially Cb.

Claim 16

The article of claim 15 wherein said substrate consists essentially of about 15 percent Ti, about 30 percent Mo, and balance essentially Cb.

Claim 17

The article of claim 15 wherein said substrate consists essentially of about 25 percent Ti, about 30 percent Mo, and balance essentially Cb.

Claim 18

The article of claim 15 wherein said substrate consists essentially of about 25 percent Ti, about 15 percent Mo, and balance eSsentially Cb.

Claim 19

The article of claim 6 wherein said substrate consists essentially of 15 to 25 percent Ti, up to 40 percent in the aggregate of Mo and Ta, the weight ratio of Mo to Ta in said substrate being from about 1:2 to about 2:1, and balance essentially Cb.