WE CLAIM:
1. An article comprising:
a substrate comprising a precipitate-strengthened alloy, the alloy comprising
a) a population of gamma-prime precipitates, the population having a multimodal size distribution with at least one mode corresponding to a size of less than about 100 nanometers; or
b) a population of gamma-double-prime precipitates having a median size less than about 300 nanometers;
and
a coating disposed over the substrate, wherein the coating comprises at least two elements, and wherein the coating further comprises a plurality of prior particles and wherein at least a portion of the coating is substantially free of rapid solidification artifacts.
2. The article as claimed in claim 1, wherein at least about 10 volume percent of the coating is substantially free of the rapid solidification artifacts.
3. The article as claimed in claim 1, wherein at least about 50 volume percent of the coating is substantially free of the rapid solidification artifacts.
4. The article as claimed in claim 1, wherein the substrate comprises a nickel-based superalloy, a nickel-iron-based superalloy, or a cobalt-based superalloy.
5. The article as claimed in claim 1, wherein the substrate comprises Rene 88, Rene 88DT, Rene 104, Rene 65, Rene 95, RR1000, Udimet 500, Udimet 520, Udimet 700, Udimet 720, Udimet 720LI, Waspaloy, Astroloy, Discaloy, AF115, ME16, N18, or IN100.

6. The article as claimed in claim 1, wherein the substrate comprises IN718 alloy, IN 725 alloy, or IN706 alloy.
7. The article as claimed in claim 1, wherein the coating comprises aluminum, chromium, and M, wherein M is at least one element selected from the group consisting of nickel, cobalt, and iron.

8. The article as claimed in claim 7, wherein the coating comprises at least about 5 weight percent aluminum.
9. The article as claimed in claim 7, wherein the coating comprises a MCrAlX composition, wherein X comprises at least one element selected from the group consisting of yttrium, rhenium, tantalum, molybdenum, rare earth elements, hafnium, zirconium, silicon, and combinations thereof.

10. The article as claimed in claim 7, wherein the coating comprises cobalt; from about 28 percent to about 35 percent nickel; from about 17 percent to about 25 percent chromium; from about 5 percent to about 15 percent aluminum; and from about 0.01 to about 1 percent yttrium.
11. The article as claimed in claim 7, wherein the coating comprises a gamma phase and a beta phase.
12. The article as claimed in claim 11, wherein the coating comprises less than 1 percent sigma phase by volume.
13. The article as claimed in claim 11, wherein the gamma phase is present at a concentration of at least about 25 volume percent of the coating.
14. The article as claimed in claim 13, wherein the beta phase is present at a concentration of at least about 10 volume percent of the coating.
15. The article as claimed in claim 1, wherein the coating is disposed in direct contact with the substrate at an interface, and wherein an interdiffusion zone

between the coating and the substrate has a thickness of less than about 5 micrometers.
16. The article as claimed in claim 1, wherein the article is a component of a gas turbine assembly.
17. The article as claimed in claim 1, wherein the article is a turbine disk.
18. An article comprising:
a substrate comprising a nickel-based superalloy, the nickel-based superalloy comprising a population of gamma-prime precipitates, the population having a multimodal size distribution with at least one mode corresponding to a size of less than about 100 nanometers; and
a coating disposed over the substrate at an interface, the coating comprising
a) a MCrAlX composition,
b) a plurality of prior particle boundaries, and
c) at least about 25 percent gamma phase by volume of the coating and beta phase in a range from about 10 percent to about 75 percent by volume of the coating;
wherein at least about 50 volume percent of the coating is substantially free of rapid solidification artifacts; and
wherein an interdiffusion zone extending from the interface into the substrate has a thickness of less than about 5 micrometers.
19. A method comprising:
heat-treating a quantity of metallic powder, the powder having particulates comprising at least two elements and a plurality of rapid solidification artifacts

present within the particulates, wherein the heat-treating is performed at a combination of time and temperature effective to remove substantially all of the rapid solidification artifacts from the powder, thereby forming a processed powder having a desired particle size distribution.
20. The method as claimed in claim 19, wherein heat-treating further includes agitating the powder during heat-treatment.
21. The method as claimed in claim 19, further comprising mechanically processing sintered material formed during the heat-treating.
22. The method as claimed in claim 21, wherein mechanically processing comprises milling the sintered material.
23. The method as claimed in claim 19, further comprising disposing a coating material on a substrate, wherein the processed powder is used as a feedstock for the coating material.
24. The method as claimed in claim 23, wherein the disposing step comprises spraying the feedstock using a technique that does not melt a substantial portion of the particulates in the feedstock.
25. The method as claimed in claim 24, wherein the technique includes cold-spraying, flame spraying, liquid injection flame spraying, air plasma spraying, liquid injection air plasma spraying, high-velocity oxyfuel spraying, liquid injection high velocity oxyfuel spraying, high-velocity air-fuel spraying, or liquid injection high-velocity air-fuel spraying.
26. The method as claimed in claim 24, wherein the technique includes liquid injection high velocity air-fuel spraying.
27. The method as claimed in claim 23, wherein the substrate comprises a nickel-based superalloy, a nickel-iron-based superalloy, or a cobalt-based superalloy.

28. The method as claimed in claim 19, wherein the particulates comprise a MCrAlY composition.
29. The method as claimed in claim 28, wherein the composition comprises cobalt; from about 28 percent to about 35 percent nickel; from about 17 percent to about 25 percent chromium; from about 5 percent to about 15 percent aluminum; and from about 0.01 to about 1 percent yttrium.
30. The method as claimed in claim 28, wherein the coating comprises beta phase, at least about 25 percent gamma phase by volume, and less than about 1 percent sigma phase by volume.
31. A method comprising:
heat-treating a quantity of powder having particulates comprising a MCrAlX composition at a temperature in a range from about 925 degrees Celsius to about 1200 degrees Celsius for at least about 5 minutes to form a processed powder; and
disposing a coating material on a substrate using cold-spraying, flame spraying, air plasma spraying, high-velocity oxyfuel spraying, or high-velocity air-fuel spraying, wherein the processed powder is used as a feedstock for the coating material, and wherein the substrate comprises a nickel-based superalloy;
wherein the disposing step comprises spraying the feedstock using a technique that does not melt a substantial portion of the particulates in the feedstock.
32. A method comprising:
disposing a coating onto a substrate by spraying a feedstock, the feedstock comprising a plurality of particulates comprising at least two elements and having at least a portion of the plurality of particulates substantially free of rapid solidification artifacts;
wherein spraying the feedstock comprises using a deposition technique that does not melt a substantial portion of the particulates in the feedstock;

wherein the substrate comprises a precipitate-strengthened alloy, the alloy comprising
a) a population of gamma-prime precipitates, the population having a multimodal size distribution with at least one mode corresponding to a size of less than about 100 nanometers; or b) a population of gamma-double-prime precipitates having a median size less than about 300 nanometers.
33. The method as claimed in claim 32, wherein the substrate comprises a nickel-based superalloy, a nickel-iron-based superalloy, or a cobalt-based superalloy.
34. The method as claimed in claim 32, wherein the feedstock comprises a MCrAlY composition.
35. The method as claimed in claim of claim 34, wherein the feedstock comprises cobalt; from about 28 percent to about 35 percent nickel; from about 17 percent to about 25 percent chromium; from about 5 percent to about 15 percent aluminum; and from about 0.01 to about 1 percent yttrium.
36. The method as claimed in claim 34, wherein the feedstock comprises a gamma phase and a beta phase.
37. The method as claimed in claim 36, wherein the feedstock includes less than about 1 percent sigma phase by volume.
38. The method as claimed in claim 36, wherein the coating is disposed in direct contact with the substrate at an interface, and wherein an interdiffusion zone extending from the interface into the substrate has a thickness of less than about 5 micrometers.
39. A method comprising:
disposing a coating onto a substrate by spraying a feedstock, the feedstock comprising a plurality of particulates comprising a MCrAlX composition and

having at least a portion of the plurality of particulates substantially free of rapid solidification artifacts;
wherein spraying the feedstock comprises using a deposition technique that does not melt a substantial portion of the particulates in the feedstock;
wherein the substrate comprises a nickel-based superalloy comprising a population of gamma-prime precipitates, the population having a multimodal size distribution with at least one mode corresponding to a size of less than about 100 nanometers.