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US-20260125780-A1 - MAGNESIUM ALLOY AND METHOD FOR PRODUCING SAME

US20260125780A1US 20260125780 A1US20260125780 A1US 20260125780A1US-20260125780-A1

Abstract

Provided is a magnesium alloy having high strength and high thermal conductivity containing a atom % of Zn and b atom % of Y, a remainder consisting of Mg and unavoidable impurities, where a and b satisfy formulas 1 to 8. The magnesium alloy contains an Mg 3 Zn 3 Y 2 phase or both an Mg 3 Zn 3 Y 2 phase and an Mg 3 Zn 6 Y phase and does not contain a long period stacking ordered phase. (Formula 1) a=0.5 (0.25≤b≤1.2) (Formula 2) b=1.2 (0.5≤a≤1.62) (Formula 3) a=1.35b (1.2≤b≤3) (Formula 4) b=3 (4.05≤a≤7) (Formula 5) a=7 (0.25≤b≤3) (Formula 6) b=0.25 (0.5≤a≤7) (Formula 7) a=4.2b+0.7 (0.25≤b≤1.5) (Formula 8) b=0.25 (0.5≤a≤1.75).

Inventors

  • Yoshihito Kawamura
  • Shinichi Inoue

Assignees

  • NATIONAL UNIVERSITY CORPORATION KUMAMOTO UNIVERSITY

Dates

Publication Date
20260507
Application Date
20231006
Priority Date
20221007

Claims (13)

  1. 1 . A magnesium alloy comprising: a atom % of Zn; b atom % of Y; and a remainder consisting of Mg and unavoidable impurities, wherein a Zn content of the a atom % and a Y content of the b atom % are set in a range enclosed by straight lines represented by the following (1) to (8) according to coordinates (b, a) where a is taken on a vertical axis and b is taken on a horizontal axis, the magnesium alloy contains a Mg 3 Zn 3 Y 2 phase or both a Mg 3 Zn 3 Y 2 phase and a Mg 3 Zn 6 Y phase, and the magnesium alloy does not contain a long period stacking ordered structure phase. (1) When b is in a range defined by the following Formula 1a, a straight line represented by the following Formula 1b is obtained. 0 . 2 ⁢ 5 ≤ b ≤ 1 .09 ( Formula ⁢ 1 ⁢ a ) a = 0. 5 ( Formula ⁢ 1 ⁢ b ) (2) When b is in a range defined by the following Formula 2a, a straight line represented by the following Formula 2b is obtained. 1.09 ≤ b ≤ 1.2 ( Formula ⁢ 2 ⁢ a ) a = 2.91 b - 2 . 6 ⁢ 7 ( Formula ⁢ 2 ⁢ b ) (3) When a is in a range defined by the following Formula 3a, a straight line represented by the following Formula 3b is obtained. 0.82 ≤ a ≤ 1.62 ( Formula ⁢ 3 ⁢ a ) b = 1. 2 ( Formula ⁢ 3 ⁢ b ) (4) When b is in a range defined by the following Formula 4a, a straight line represented by the following Formula 4b is obtained. 1.2 ≤ b ≤ 3 ( Formula ⁢ 4 ⁢ a ) a = 1. 3 ⁢ 5 ⁢ b ( Formula ⁢ 4 ⁢ b ) (5) When a is in a range defined by the following Formula 5a, a straight line represented by the following Formula 5b is obtained. 4.05 ≤ a ≤ 7 ( Formula ⁢ 5 ⁢ a ) b = 3 ( Formula ⁢ 5 ⁢ b ) (6) When b is in a range defined by the following Formula 6a, a straight line represented by the following Formula 6b is obtained. 1.5 ≤ b ≤ 3 ( Formula ⁢ 6 ⁢ a ) a = 7 ( Formula ⁢ 6 ⁢ b ) (7) When b is in a range defined by the following Formula 7a, a straight line represented by the following Formula 7b is obtained. 0.25 ≤ b ≤ 1.5 ( Formula ⁢ 7 ⁢ a ) a = 4. 2 ⁢ b + 0 . 7 ( Formula ⁢ 7 ⁢ b ) (8) When a is in a range defined by the following Formula 8a, a straight line represented by the following Formula 8b is obtained. 0.5 ≤ a ≤ 1.75 ( Formula ⁢ 8 ⁢ a ) b = 0. 2 ⁢ 5 ( Formula ⁢ 8 ⁢ b )
  2. 2 . The magnesium alloy according to claim 1 , wherein the magnesium alloy has a thermal conductivity of 90 W/m·K or more.
  3. 3 . The magnesium alloy according to claim 1 , wherein the magnesium alloy contains any one element selected from the group consisting of Yb in an amount of 0.05 atom % or more and 0.6 atom % or less, Be in an amount of 0.03 atom % or more and 0.3 atom % or less, Ca in an amount of 1.0 atom % or more and 2.0 atom % or less, and Sr in an amount of 0.1 atom % or more and 2.0 atom % or less.
  4. 4 . The magnesium alloy according to claim 1 , wherein Zn/Y, which is a composition ratio of Zn to Y in the magnesium alloy, is in a range of 2 or more and 5 or less.
  5. 5 . The magnesium alloy according to claim 1 , wherein the magnesium alloy has a structure in which the Mg 3 Zn 3 Y 2 phase is not formed in a network shape at grain boundaries or a structure in which both the Mg 3 Zn 3 Y 2 phase and the Mg 3 Zn 6 Y phase are not formed in a network shape at grain boundaries.
  6. 6 . The magnesium alloy according to claim 1 , wherein the magnesium alloy has a yield strength of 300 MPa or more and an elongation of 5% or more.
  7. 7 . A method for manufacturing a magnesium alloy containing an a atom % of Zn, a b atom % of Y, and a remainder consisting of Mg and unavoidable impurities, the method comprising: a step (a) of forming a cast material by casting the magnesium alloy at a solidification rate of less than 1000 K/sec, wherein a Zn content of a atom % and a Y content of b atom % are set in a range enclosed by straight lines represented by the following (1) to (8) according to coordinates (b, a) where a is taken on a vertical axis and b is taken on a horizontal axis, the cast material contains a Mg 3 Zn 3 Y 2 phase or both a Mg 3 Zn 3 Y 2 phase and a Mg 3 Zn 6 Y phase, and the cast material does not contain a long period stacking ordered structure phase. (1) When b is in a range defined by the following Formula 1a, a straight line represented by the following Formula 1b is obtained. 0 . 2 ⁢ 5 ≤ b ≤ 1 .09 ( Formula ⁢ 1 ⁢ a ) a = 0. 5 ( Formula ⁢ 1 ⁢ b ) (2) When b is in a range defined by the following Formula 2a, a straight line represented by the following Formula 2b is obtained. 1.09 ≤ b ≤ 1.2 ( Formula ⁢ 2 ⁢ a ) a = 2.91 b - 2 . 6 ⁢ 7 ( Formula ⁢ 2 ⁢ b ) (3) When a is in a range defined by the following Formula 3a, a straight line represented by the following Formula 3b is obtained. 0.82 ≤ a ≤ 1.62 ( Formula ⁢ 3 ⁢ a ) b = 1. 2 ( Formula ⁢ 3 ⁢ b ) (4) When b is in a range defined by the following Formula 4a, a straight line represented by the following Formula 4b is obtained. 1.2 ≤ b ≤ 3 ( Formula ⁢ 4 ⁢ a ) a = 1. 3 ⁢ 5 ⁢ b ( Formula ⁢ 4 ⁢ b ) (5) When a is in a range defined by the following Formula 5a, a straight line represented by the following Formula 5b is obtained. 4.05 ≤ a ≤ 7 ( Formula ⁢ 5 ⁢ a ) b = 3 ( Formula ⁢ 5 ⁢ b ) (6) When b is in a range defined by the following Formula 6a, a straight line represented by the following Formula 6b is obtained. 1.5 ≤ b ≤ 3 ( Formula ⁢ 6 ⁢ a ) a = 7 ( Formula ⁢ 6 ⁢ b ) (7) When b is in a range defined by the following Formula 7a, a straight line represented by the following Formula 7b is obtained. 0.25 ≤ b ≤ 1.5 ( Formula ⁢ 7 ⁢ a ) a = 4. 2 ⁢ b + 0 . 7 ( Formula ⁢ 7 ⁢ b ) (8) When a is in a range defined by the following Formula 8a, a straight line represented by the following Formula 8b is obtained. 0.5 ≤ a ≤ 1 .75 ( Formula ⁢ 8 ⁢ a ) b = 0. 2 ⁢ 5 ( Formula ⁢ 8 ⁢ b )
  8. 8 . The method for manufacturing a magnesium alloy according to claim 7 , further comprising: a step (b) of forming a heat-treated material by performing heat treatment on the cast material after the step (a), wherein the heat-treated material has a thermal conductivity of 90 W/m K or more, the heat-treated material contains the Mg 3 Zn 3 Y 2 phase or both the Mg 3 Zn 3 Y 2 phase and the Mg 3 Zn 6 Y phase, and the heat-treated material does not contain the long period stacking ordered structure phase.
  9. 9 . The method for manufacturing a magnesium alloy according to claim 8 , wherein conditions for performing the heat treatment are set to at a temperature of 200° C. or more and 500° C. or less and a heat treatment time of 48 hours or less.
  10. 10 . The magnesium alloy according to claim 7 , wherein the magnesium alloy contains any one element selected from the group consisting of Yb in an amount of 0.05 atom % or more and 0.6 atom % or less, Be in an amount of 0.03 atom % or more and 0.3 atom % or less, Ca in an amount of 1.0 atom % or more and 2.0 atom % or less, and Sr in an amount of 0.1 atom % or more and 2.0 atom % or less.
  11. 11 . The method for manufacturing a magnesium alloy according to any one of claim 7 , wherein Zn/Y, which is a composition ratio of Zn to Y in the cast material, is in a range of 2 or more and 5 or less.
  12. 12 . The method for manufacturing a magnesium alloy according to claim 8 , further comprising: a step (c) of forming a plastically processed material by performing plastic processing on the heat-treated material after the step (a) or the step (b), wherein the plastically processed material has a structure in which the Mg 3 Zn 3 Y 2 phase is not formed in a network shape at grain boundaries or a structure in which both the Mg 3 Zn 3 Y 2 phase and the Mg 3 Zn 6 Y phase are not formed in a network shape at grain boundaries.
  13. 13 . The method for manufacturing a magnesium alloy according to claim 12 , wherein the plastically processed material has a yield strength of 300 MPa or more and an elongation of 5% or more.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application is a national stage application of International Patent Application No. PCT/JP2023/037309, filed on Oct. 6, 2023, which claims priority of the Japanese Patent Application No. 2022-162301, filed on Oct. 7, 2022, both of which are incorporated by references in their entities. TECHNICAL FIELD The present invention relates to a magnesium alloy and a manufacturing method of the same. BACKGROUND As more transportation equipment becomes electrified, there is a demand for the development of magnesium alloys that is lightweight and that has high heat dissipation, high strength, and high thermal conductivity. However, since the thermal conductivity of AZ91D (ASTM designation) that is a typical magnesium alloy is approximately 60 W/m K, when the AZ91D is used in components that are exposed to a high-temperature usage environment or that generate heat during use, heat dissipation may not be performed well, and thermal deformation may occur in the components (refer to, for example, paragraph of Patent Document 1). In addition, the strength of the components may be insufficient. DOCUMENT IN THE EXISTING ART Patent Document 1: JP 2012-197490 A SUMMARY Problem to be Solved by the Invention An object of one aspect of the invention is to provide a magnesium alloy having high thermal conductivity or a manufacturing method of the same. In addition, an object of one aspect of the invention is to provide a magnesium alloy having high strength and high thermal conductivity or a manufacturing method of the same. In addition, an object of one aspect of the invention is to provide a magnesium alloy having high strength, high thermal conductivity, and non-flammability or a manufacturing method of the same. Means for Solving Problem Hereinafter, various aspects of the invention will be described. A magnesium alloy contains a atom % of Zn; b atom % of Y; and a remainder consisting of Mg and unavoidable impurities. A Zn content of a atom % and a Y content of b atom % are set in a range enclosed by straight lines represented by the following (1) to (8) according to coordinates (b, a) where a is taken on a vertical axis and b is taken on a horizontal axis. The magnesium alloy contains a Mg3Zn3Y2 phase or both a Mg3Zn3Y2 phase and a Mg3Zn6Y-phase. The magnesium alloy does not contain a long period stacking ordered structure phase. (1) When b is in a range defined by the following Formula 1a, a straight line represented by the following Formula 1b is obtained. 0.2⁢5≤b≤1.09(Formula⁢ 1⁢a)a=0.5(Formula⁢ 1⁢b) (2) When b is in a range defined by the following Formula 2a, a straight line represented by the following Formula 2b is obtained. 1.09≤b≤1.2(Formula⁢ 2⁢a)a=2.91b-2.6⁢7(Formula⁢ 2⁢b) (3) When a is in a range defined by the following Formula 3a, a straight line represented by the following Formula 3b is obtained. 0.82≤a≤1.62(Formula⁢ 3⁢a)b=1.2(Formula⁢ 3⁢b) (4) When b is in a range defined by the following Formula 4a, a straight line represented by the following Formula 4b is obtained. 1.2≤b≤3(Formula⁢ 4⁢a)a=1.3⁢5⁢b(Formula⁢ 4⁢b) (5) When a is in a range defined by the following Formula 5a, a straight line represented by the following Formula 5b is obtained. 4.05≤a≤7(Formula⁢ 5⁢a)b=3(Formula⁢ 5⁢b) (6) When b is in a range defined by the following Formula 6a, a straight line represented by the following Formula 6b is obtained. 1.5≤b≤3(Formula⁢ 6⁢a)a=7(Formula⁢ 6⁢b) (7) When b is in a range defined by the following Formula 7a, a straight line represented by the following Formula 7b is obtained. 0.25≤b≤1.5(Formula⁢ 7⁢a)a=4.2⁢b+0.7(Formula⁢ 7⁢b) (8) When a is in a range defined by the following Formula 8a, a straight line represented by the following Formula 8b is obtained. 0.5≤a≤1.75(Formula⁢ 8⁢a)b=0.2⁢5(Formula⁢ 8⁢b) Furthermore, the magnesium alloy has a thermal conductivity of 90 W/m·K or more (preferably 100 W/m·K or more, more preferably 110 W/m·K or more, and still more preferably 130 W/m·K or more). Furthermore, the magnesium alloy contains any one element selected from the group consisting of Yb in an amount of 0.05 atom % or more and 0.6 atom % or less, Be in an amount of 0.03 atom % or more and 0.3 atom % or less, Ca in an amount of 1.0 atom % or more and 2.0 atom % or less, and Sr in an amount of 0.1 atom % or more and 2.0 atom % or less. Furthermore, Zn/Y, which is a composition ratio of Zn to Y in the magnesium alloy, is in a range of 2 or more and 5 or less. Furthermore, the magnesium alloy has a structure in which the Mg3Zn3Y2 phase is not formed in a network shape at grain boundaries (a structure in which a network is formed in a collapsed state) or a structure in which both the Mg3Zn3Y2 phase and the Mg3Zn6Y phase are not formed in a network shape at grain boundaries (a structure in which a network is formed in a collapsed state). Furthermore, the magnesium alloy has a yield strength of 300 MPa or more and an elongation of 5% or more. A met