Ductile cobalt-based Laves phase alloys
View Patent ↗A Co—Mo—Cr Co-based alloy and overlay for wear and corrosion applications. The Mo:Si ratio is between about 15:1 and about 22:1 for enhanced ductility with a Laves phase.
1. A Co—Mo—Cr Co-based metallic composition for forming a wear- and corrosion-resistant overlay on a metallic substrate, the metallic composition comprising, by weight percent:
14-17 Cr,
18-24 Mo,
0.75-1.35 Si,
0.1-0.5 C, and
balance Co,
wherein the metallic composition has a Mo:Si ratio of between 15:1 and 22:1, and
wherein the wear- and corrosion-resistant overlay formed by the metallic composition has a hypoeutectic microstructure that comprises between about 8 vol % and about 30 vol % Laves phase.
2. The Co-based metallic composition of claim 1 wherein the metallic composition has a hardness between about 40 and about 52 HRC (Rockwell C scale).
3. The Co-based metallic composition of claim 1 consisting of, by weight percent:
14-17 Cr,
18-24 Mo,
0.75-1.35 Si,
0.1-0.5 C,
up to about 1% B,
up to about 3% Ni,
up to about 3% Fe,
wherein the total concentration of B, Ni, Fe is less than about 8 wt %, and
balance Co.
4. The Co-based metallic composition of claim 3 wherein the Mo:Si ratio is between 16:1 and 19:1.
5. The Co-based metallic composition of claim 3 wherein the metallic composition has a hardness between about 40 and about 52 HRC (Rockwell C scale).
6. The Co-based metallic composition of claim 1 wherein the Mo:Si ratio is between 16:1 and 19:1.
7. The Co-based metallic composition of claim 1 further comprising, by weight percent:
up to about 1% B
up to about 3% Ni
up to about 3% Fe;
and additional trace elements wherein the total concentration of B, Ni, Fe, and additional trace elements is less than about 8 wt %.
8. The Co-based metallic composition of claim 1 further comprising a grain refiner selected from the group of grain refiners consisting of V, Zr, Hf, Ta, and rare earth elements, and any combination thereof.
9. The Co-based metallic composition of claim 1 consisting of, by weight percent:
14-17% Cr,
18-24% Mo,
0.75-1.35% Si,
0.1-0.5% C,
up to 2% of a grain refiner selected from the group of grain refiners consisting of V, Zr, Hf, Ta, and rare earth elements, and any combination thereof, and
balance Co.
10. The Co-based metallic composition of claim 9 wherein the Mo:Si ratio is between 16:1 and 19:1.
11. The Co-based metallic composition of claim 9 wherein the metallic composition has a hardness between about 40 and about 52 HRC (Rockwell C scale).
12. The Co-based metallic composition of claim 1 consisting of, by weight percent:
16.2% Cr,
22.3% Mo,
1.27% Si,
0.21% C,
up to about 1% B,
up to about 3% Ni,
up to about 3% Fe,
wherein the total concentration of B, Ni, Fe is less than about 8 wt %, and
balance Co.
13. The Co-based metallic composition of claim 12 wherein the Mo:Si ratio is between 16:1 and 19:1.
14. The Co-based metallic composition of claim 12 wherein the metallic composition has a hardness between about 40 and about 52 HRC (Rockwell C scale).
15. The Co-based metallic composition of claim 1 wherein the composition is Mn-free.
16. The Co-based metallic composition of claim 15 wherein the composition is further Cu-free and free of all alloying elements having a material effect on metallurgical properties other than Cr, Mo, Si, and C in the Co matrix.
17. The Co-based metallic composition of claim 1 consisting of, by weight percent:
14-17 Cr,
18-24 Mo,
0.75-1.35 Si,
0.1-0.5 C,
up to about 1% B,
up to about 3% Ni,
up to about 3% Fe,
wherein the total concentration of B, Ni, Fe is less than about 8 wt %,
up to 2% of a grain refiner selected from the group of grain refiners consisting of V, Zr, Hf, Ta, and rare earth elements, and any combination thereof, and
balance Co.
18. The Co-based metallic composition of claim 17 wherein the Mo:Si ratio is between 16:1 and 19:1.
19. The Co-based metallic composition of claim 17 wherein the metallic composition has a hardness between about 40 and about 52 HRC (Rockwell C scale).