HIGH-ENTROPY SUPERALLOY

• US 20170369970A1
• Filed: 10/13/2016
• Published: 12/28/2017
• Est. Priority Date: 06/22/2016
• Status: Active Grant

• Current Assignee: National Tsing Hua University
• Original Assignee: National Tsing Hua University
• Inventors: YEH, AN-CHOU, TSAO, TE-KANG
• Granted Patent: US 10,472,702 B2
• Time in Patent Office: Days
• CPC Class Codes: C22C 19/058 without Mo and W
• CPC Class Codes: C22C 30/00 Alloys containing less than 50% by weight of each constituent

Abstract

Differing from traditional alloys often containing one primary elemental composition, the present invention reforms a conventional superalloy to a high-entropy superalloy by redesigning the elemental compositions of the conventional superalloy based on a mixing entropy formula. Particularly, this high-entropy superalloy shows advantages of light weight and low cost under the premise of containing a low amount of expensive metal composition. The proposed high-entropy superalloy of the present invention comprises a primary elemental composition and at least one principal strengthening elemental composition, wherein the primary elemental composition has a first element content of at least 35 at % and each of the principal strengthening elemental compositions have a second element content of over 5 at %. Moreover, a variety of experimental results have proved that the high-entropy superalloy simultaneously possesses a variety of excellent high-temperature mechanical properties, such as high mechanical strength, high corrosion resistance, high oxidation resistance, and high creep resistance.

Claims

1. A high-entropy superalloy, comprising:

at least one primary elemental composition, being a siderophile element for forming a base phase structure of the high-entropy superalloy;

wherein the primary elemental composition has a first element content of at least 35 at %; and

at least one principal strengthening elemental composition for forming at least one precipitation strengthening phase structure, wherein each the principal strengthening elemental composition has a second element content of over 5 at %;

wherein the first element content and the second element content are determined by a mixing entropy of the primary elemental composition and the principal strengthening elemental composition, and the absolute value of the mixing entropy being over 1.5 R.

2. The high-entropy superalloy of claim 1, wherein the siderophile element is selected from the group consisting of:

nickel (Ni), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), and platinum group element (PGE).

3. The high-entropy superalloy of claim 1, wherein the principal strengthening elemental composition is selected from the group consisting of:

aluminum (Al), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), niobium (Nb), titanium (Ti), vanadium (V), zirconium (Zr), and combination of the aforesaid two or more elements.

4. The high-entropy superalloy of claim 1, further comprising at least one grain boundary strengthening elemental composition having a third element content of less than 15 wt %.

5. The high-entropy superalloy of claim 1, being made by using a manufacturing method selected from the group consisting of:

atmospheric melting method, vacuum arc melting method, vacuum induction melting method, electric resistance wire heating method, electric induction heating method, rapidly solidification method, mechanical ball-milling method, powder metallurgic method, and additive manufacturing method.

6. The high-entropy superalloy of claim 1, wherein the base phase structure is a face centered cubic (FCC) structure.

7. The high-entropy superalloy of claim 1, wherein a product or a semi-product of the high-entropy superalloy can be a powder, a wire, a welding rod, a cored wire, or a bulk.

8. The high-entropy superalloy of claim 1, being able to be coated on the surface of a target workpiece by a processing method selected from the group consisting of:

casting method, electric-arc welding method, thermal spraying method, and thermal sintering method.

9. The high-entropy superalloy of claim 4, wherein the grain boundary strengthening elemental composition is selected from the group consisting of:

carbon (C), boron (B), hafnium (Hf), combination of the aforesaid two or more elements.

10. The high-entropy superalloy of claim 4, further comprising at least one firebrick elemental composition having a fourth element content of less than 15 wt %;

moreover, the summation of the third element content and fourth element content also being less than 15 wt %.

11. The high-entropy superalloy of claim 10, wherein the firebrick elemental composition is selected from the group consisting of:

molybdenum (Mo), tantalum (Ta), tungsten (W), rhenium (Re), ruthenium (Ru), combination of the aforesaid two or more elements.