# US 8,771,440 B2 · Ni-based single crystal superalloy > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,771,440 B2 - Document ID: US8771440B2 - Status: Granted - Kind: B2 - Application number: 12/441,017 - Filed: 2007-09-12 - Published: 2010-06-10 - Granted: 2014-07-08 - Earliest claimed: 2006-09-13 - Assignees: National Institute for Materials Science; IHI Corporation - Applicants: Akihiro Sato; Hiroshi Harada; Kyoko Kawagishi; Toshiharu Kobayashi; Tadaharu Yokokawa; Yutaka Koizumi; Yasuhiro Aoki; Mikiya Arai; Kazuyoshi Chikugo; Shoju Masaki - Inventors: Akihiro Sato; Hiroshi Harada; Kyoko Kawagishi; Toshiharu Kobayashi; Tadaharu Yokokawa; Yutaka Koizumi; Yasuhiro Aoki; Mikiya Arai; Kazuyoshi Chikugo; Shoju Masaki - Web page: https://patentgrep.com/patent/US8771440B2 ## CPC - C22C 19/057: {with the maximum Cr content being less 10%} - C22C 19/00: Alloys based on nickel or cobalt - C22C 19/007: {with a light metal (alkali metal Li, Na, K, Rb, Cs; earth alkali metal Be, Mg, Ca, Sr, Ba, Al Ga, Ge, Ti) or B, Si, Zr, Hf, Sc, Y, lanthanides, actinides, as the next major constituent} - C22C 19/03: based on nickel - C22F 1/10: of nickel or cobalt or alloys based thereon - C22C: ALLOYS (treatment of alloys C21D, C22F) - C22F: CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass, C23F17/00) ## Abstract A Ni-based single crystal superalloy according to the invention has, for example, a composition including: 5.0 to 7.0 wt % of Al, 4.0 to 10.0 wt % of Ta, 1.1 to 4.5 wt % of Mo, 4.0 to 10.0 wt % of W, 3.1 to 8.0 wt % of Re, 0.0 to 2.0 wt % of Hf, 2.5 to 8.5 wt % of Cr, 0.0 to 9.9 wt % of Co, 0.0 to 4.0 wt % of Nb, and 1.0 to 14.0 wt % of Ru in terms of weight ratio; and the remainder including Ni and incidental impurities. In addition, the contents of Cr, Hf and Al are preferably set so as to satisfy the equation OP≧108. According to the Ni-based single crystal superalloy of the invention, high creep strength can be maintained and the oxidation resistance can be improved. ## Claims ### Claim 1 A Ni-based single crystal superalloy which has a composition including: 5.0 to 7.0 wt % of Al, 4.0 to 10.0 wt % of Ta, 1.1 to 4.5 wt % of Mo, 4.0 to 10.0 wt % of W, 3.1 to 8.0 wt % of Re, 0.0 to 2.0 wt % of Hf, 5.1 wt % to 8.5 wt % of Cr, 0.0 to 9.9 wt % of Co, 0.0 to 4.0 wt % of Nb, and 1.0 to 14.0 wt % of Ru in terms of weight ratio; and the remainder including Ni and incidental impurities, and wherein when a formula, that is, an oxidation parameter (OP)=5.5×[Cr (wt %)]+15.0×[Al (wt %)]+9.5×[Hf (wt %)] is set, the equation OP≧108 is satisfied, and wherein when a lattice constant of a matrix is denoted by al and a lattice constant of a precipitated phase is denoted by a2, the equation a2<0.999a1 is satisfied. ### Claim 2 (depends on 1) The Ni-based single crystal superalloy according to claim 1, wherein Hf is in the range of 0.0 to 0.5 wt %. ### Claim 3 (depends on 1) The Ni-based single crystal superalloy according to claim 1, wherein Hf is in the range of 0.0 to 0.5 wt %, Mo is in the range of 2.1 to 4.5 wt %, and Ta is in the range of 4.0 to 6.0 wt %. ### Claim 4 (depends on 1) The Ni-based single crystal superalloy according to claim 1, wherein when a formula, that is, an oxidation parameter (OP)=5.5×[Cr (wt %)]+15.0×[Al (wt %)]+9.5×[Hf(wt %)] is set, the equation OP≦113 is satisfied. ### Claim 5 (depends on 1) The Ni-based single crystal superalloy according to claim 1, further including 1.0 wt % or less of Ti in terms of weight ratio. ### Claim 6 (depends on 1) The Ni-based single crystal superalloy according to claim 1, wherein when a lattice constant of a matrix is denoted by al and a lattice constant of a precipitated phase is denoted by a2, the equation a2<0.9965a1 is satisfied. ### Claim 7 (depends on 1) The Ni-based single crystal superalloy according to claim 1, wherein when a formula, that is, P=−200[Cr (wt %)]+80[Mo (wt %)]−20[Mo (wt %)2+200[W (wt %)]−14[W (wt %)]2+30[Ta (wt %)]−1.5[Ta (wt %)]2+2.5[Co (wt %)]+1200[Al (wt %)]−100[Al (wt %)]2+100[Re (wt %)]+1000[Hf(wt %)]−2000[Hf (wt %)]2+700[Hf (wt %)]3 is set, the equation P<4500 is satisfied. ### Claim 8 A Ni-based single crystal superalloy which has a composition including: 5.0 to 6.5 wt % of Al, 4.0 to 6.5 wt % of Ta, 2.1 to 4.0 wt % of Mo, 4.0 to 6.0 wt % of W, 4.5 to 7.5 wt % of Re, 0.1 to 2.0 wt % of Hf, 5.1 wt % to 8.5 wt % of Cr, 4.5 to 9.5 wt % of Co, 0.0 to 1.5 wt % of Nb, and 1.5 to 6.5 wt % of Ru in terms of weight ratio; and the remainder including Ni and incidental impurities, and wherein when a formula, that is, an oxidation parameter (OP)=5.5×[Cr (wt %)]+15.0 ×[Al (wt %)]+9.5×[Hf (wt %)] is set, the equation OP≧108 is satisfied, and wherein when a lattice constant of a matrix is denoted by al and a lattice constant of a precipitated phase is denoted by a2, the equation a2≦0.999a1 is satisfied. ### Claim 9 (depends on 8) The Ni-based single crystal superalloy according to claim 8, wherein Hf is in the range of 0.1 to 0.5 wt %. ### Claim 10 A Ni-based single crystal superalloy which has a composition including: 5.5 to 5.9 wt % of Al, 4.7 to 5.6 wt % of Ta, 2.2 to 2.8 wt % of Mo, 4.4 to 5.6 wt % of W, 5.0 to 6.8 wt % of Re, 0.1 to 2.0 wt % of Hf, 5.1 wt % to 6.7 wt % of Cr, 5.3 to 9.0 wt % of Co, 0.0 to 1.0 wt % of Nb, and 2.3 to 5.9 wt % of Ru in terms of weight ratio; and the remainder including Ni and incidental impurities, and wherein when a formula, that is, an oxidation parameter (OP)=5.5×[Cr (wt %)]+15.0 ×[Al (wt %)]+9.5×[Hf (wt %)]is set, the equation OP≧108 is satisfied, and wherein when a lattice constant of a matrix is denoted by al and a lattice constant of a precipitated phase is denoted by a2, the equation a2<0.999a1 is satisfied. ### Claim 11 (depends on 10) The Ni-based single crystal superalloy according to claim 10, wherein Hf is in the range of 0.1 to 0.5 wt %.