HIGH-STRENGHT Co-BASED ALLOY WITH ENHANCED WORKABILITY AND PROCESS FOR PRODUCING THE SAME

• US 20080185075A1
• Filed: 04/07/2008
• Published: 08/07/2008
• Est. Priority Date: 10/11/2006
• Status: Active Grant

• Current Assignee: Japan Science And Technology Agency
• Original Assignee: Japan Science And Technology Agency
• Inventors: KAINUMA, Ryosuke, OMORI, Toshihiro, SUTOU, Yuji, ISHIDA, Kiyohito, YAMAUCHI, Kiyoshi
• Granted Patent: US 8,529,710 B2
• Time in Patent Office: Days
• US Class Current: 148/538
• CPC Class Codes: C22C 19/07 based on cobalt

Abstract

A Co-based alloy being useful as a spiral spring, common spring, wire, cable guide, steel belt, build-up material, guide wire, stent, catheter, etc. There is provided a Co-based alloy having a composition of Co—Al binary system containing 3-13% Al loaded with at least one workability enhancing element selected from among 001 to 50% Ni, 0.01 to 40% Fe and 0.01 to 30% Mn and having a lamellar structure wherein f.c.c. structure α-phase and β(B2)-phase are repeated in layers. The lamellar structure is so regulated that the occupancy ratio of the whole structure is 30 vol. % or above and the layer spacing is 100 μm or less. The Co-based alloy may contain at least one optional component selected from among Ga, Cr, V, Ti, Mo, Nb, Zr, W, Ta, Hf, Si, Rh, Pd, Ir, Pt, Au, B, C and P may be added in a total amount of 0.01 to 60%.

Claims

1. A high-strength Co-based alloy comprising:

a fundamental composition which comprises, on the basis of mass percent, one or more of 0.01 to 60% of workability enhancing elements selected from 0.01 to 50% of Ni, 0.01 to 40% of Fe and 0.01 to 30% of Mn, and 3 to 13% of Al, and the balance being cobalt and impurities; and

a metallic structure having a lamellar structure wherein a f.c.c. structure α

-phase and β

(B2)-phase with an interlayer spacing of 100 μ

m or less are repeated in layers and the occupancy ratio is 30% by volume or more.

3. A process for producing the high-strength co-based alloy, comprising the steps of:

dissolving the Co-based alloy having the composition according to claim 1 or 2;

cooling and solidifying with an average cooling rate;

500°

C./min or less in the range of 1500 to 600°

C.; and

crystallizing the f.c.c. structure α

-phase and β

(B2)-type phase, the L1₂-type γ

′

phase,

4. The process for producing the high-strength co-based alloy, comprising the steps of:

performing solution treatment at 900 to 1400°

C. the co-based alloys having the composition according to claim 1; and

precipitating the f.c.c. structure α

-phase and β

(B2)-type phase, the L1₂-type γ

′

phase, the D0₁₉-type precipitate, and/or the M₂₃C₆-type carbide so as to form the lamellar structure by aging treatment at 500 to 900°

C.

5. The process for producing the high-strength co-based alloy according to claim 3, wherein the Co-based alloy after formation of the lamellar structure is subjected to cold working at a working ratio of 10% or more.

2. The high-strength Co-based alloy, comprising a composition which comprises, on the basis of mass ratio, 3 to 13% of Al and 0.01 to 60% of workability enhancing element, and further comprises one or more members selected from the following:

0.01 to 40% of Cr, 0.01 to 30% of Mo, 0.01 to 5% of Si, 0.01 to 30% of W, 0.01 to 10% of Zr, 0.01 to 15% of Ta, 0.01 to 10% of Hf, 0.01 to 20% of Ga, 0.01 to 20% of V, 0.01 to 12% of Ti, 0.01 to 20% of Nb, 0.001 to 3% of C, 0.01 to 20% of Rh, 0.01 to 20% of Pd, 0.01 to 20% of Ir, 0.01 to 20% of Pt, 0.01 to 10% of Au, 0.001 to 1% of B, and 0.001 to 1% of P in a total of 0.001 to 60%, and the balance being cobalt without incidental impurities; and

the lamellar structure wherein the f.c.c. structure α

-phase and β

(B2)-type phase, a L1₂-type γ

′

phase, a D0₁₉-type precipitate, and/or a M₂₃C₆-type carbide with an interlayer spacing of 100 μ

m or less are repeated in layers and the occupancy ratio of the lamellar structure to the whole metallic structure is 30% by volume or more.