# US 2021/0172035 A1 · Methods of forming magnesium-based alloy articles at high strain rates > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0172035 A1 - Document ID: US20210172035A1 - Status: Published application - Kind: A1 - Application number: 17/117,254 - Filed: 2020-12-10 - Published: 2021-06-10 - Earliest claimed: 2019-12-10 - Assignees: GM Global Technology Operations LLC - Applicants: GM Global Technology Operations LLC - Inventors: Henry ZHAN - Web page: https://patentgrep.com/patent/US20210172035A1 ## CPC - C21D 8/0236: {Cold rolling} - C21D 9/32: for gear wheels, worm wheels, or the like - C21D 9/40: for rings; for bearing races - C22C 23/04: with zinc or cadmium as the next major constituent - C22F 1/06: of magnesium or alloys based thereon - C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (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; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B) - 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 Methods of making magnesium-based alloy components, such as automotive components, include treating a casting comprising a magnesium-based alloy to a first deforming process to form a preform. In one aspect, the first deforming process has a first maximum predetermined strain rate of greater than or equal to about 0.001/s to less than or equal to about 1/s in an environment having a temperature of ≥to about 250° C. to ≤to about 450° C. In another aspect, the first deforming process is cold deforming that is followed by annealing. The preform is then subjected to a second deforming process having a second maximum predetermined strain rate of ≥about 1/s to ≤about 100/s in an environment having a temperature of ≥about 150° C. to ≤about 450° C. to form the magnesium-based alloy component substantially free of cracking. A solid magnesium-based alloy component having select microstructures are also provided. ## Claims ### Claim 1 A method of making a magnesium-based alloy component comprising: treating a casting comprising a magnesium-based alloy to a first deforming process having a first maximum predetermined strain rate of greater than or equal to about 0.001/s to less than or equal to about 1/s in an environment having a temperature of greater than or equal to about 250° C. to less than or equal to about 450° C. to form a preform, wherein the magnesium-based alloy has a composition comprising zirconium at greater than or equal to 0 to less than or equal to about 1 wt. %; manganese at greater than or equal to about 0.3 wt. % to less than or equal to about 2 wt. %; scandium at greater than or equal to 0 to less than or equal to about 15 wt. %; a rare earth metal element at greater than or equal to 0 to less than or equal to about 20 wt. %; zinc at greater than or equal to 0 to less than or equal to about 6 wt. %; aluminum at greater than or equal to 0 to less than or equal to about 3 wt. %; and a balance of magnesium; and subjecting the preform to a second deforming process having a second maximum predetermined strain rate of greater than or equal to about 1/s to less than or equal to about 100/s in an environment having a temperature of greater than or equal to about 150° C. to less than or equal to about 450° C. to form the magnesium-based alloy component substantially free of cracking. ### Claim 2 (depends on 1) The method of claim 1, wherein the preform comprises one or more intermetallic species selected from the group consisting of: ZnZr, AlMn, MnSc, AlRE, where RE is a rare earth element, and combinations thereof. ### Claim 3 (depends on 1) The method of claim 1, wherein the first deforming process is selected from the group consisting of: extrusion, forging, rolling, and combinations thereof. ### Claim 4 (depends on 1) The method of claim 1, wherein the second deforming process is selected from the group consisting of: high-speed rolling, flow forming, high-speed forging, ring rolling, and combinations thereof. ### Claim 5 (depends on 1) The method of claim 1, wherein prior to the treating, heat treating the casting to homogenize the magnesium-based alloy, form thermally-stable refined precipitates, or both homogenize the magnesium-based alloy and form thermally-stable refined precipitates. ### Claim 6 (depends on 1) The method of claim 1, wherein the preform comprises a matrix comprising a plurality of dynamically recrystallized grains having an average size of greater than or equal to about 0.1 μm to less than or equal to about 20 μm; and a plurality of coarse grains having an average size of greater than or equal to about 1 μm to less than or equal to about 200 μm, wherein the average size of the plurality of coarse grains is greater than or equal to 50% more than the average size of the dynamically recrystallized grains. ### Claim 7 (depends on 1) The method of claim 1, wherein the magnesium-based alloy comprises a plurality of domains comprising thermally-stable refined intermetallic species distributed in a matrix, wherein the matrix undergoes dynamic recrystallization during the treating to form refined grains, while dynamic recrystallization in the plurality of domains is minimized or prevented. ### Claim 8 (depends on 1) The method of claim 1, further comprising a heat treatment after the subjecting in an environment having a temperature of greater than or equal to about 150° C. to less than or equal to about 300° C. for a duration of greater than or equal to about 2 hours to less than or equal to about 100 hours to enhance mechanical properties of the magnesium-based alloy component. ### Claim 9 (depends on 1) The method of claim 1, wherein the magnesium-based alloy component is an automotive component selected from the group consisting of: an internal combustion engine component, a valve, a piston, a turbocharger component, a rim, a wheel, a ring, and combinations thereof. ### Claim 10 A method of making a magnesium-based alloy component comprising: treating a casting comprising a magnesium-based alloy to a cold deforming process in an environment having a temperature of less than or equal to about 200° C. to form a preform, wherein the magnesium-based alloy has a composition comprising zirconium at greater than or equal to 0 to less than or equal to about 1 wt. %; manganese at greater than or equal to about 0.3 wt. % to less than or equal to about 2 wt. %; scandium at greater than or equal to 0 to less than or equal to about 15 wt. %; a rare earth metal element at greater than or equal to 0 to less than or equal to about 20 wt. %; zinc at greater than or equal to 0 to less than or equal to about 6 wt. %; aluminum at greater than or equal to 0 to less than or equal to about 3 wt. %; and a balance of magnesium; annealing the preform; and subjecting the preform to a second deforming process having a maximum predetermined strain rate of greater than or equal to about 1/s to less than or equal to about 100/s in an environment having a temperature of greater than or equal to about 150° C. to less than or equal to about 450° C. to form the magnesium-based alloy component substantially free of cracking. ### Claim 11 (depends on 10) The method of claim 10, wherein the second deforming process is selected from the group consisting of: high-speed rolling, flow forming, high-speed forging, ring rolling and combinations thereof. ### Claim 12 (depends on 10) The method of claim 10, wherein prior to the treating, heat treating the casting to homogenize the magnesium-based alloy, form thermally-stable refined precipitates, or both homogenize the magnesium-based alloy and form thermally-stable refined precipitates. ### Claim 13 (depends on 10) The method of claim 10, wherein the magnesium-based alloy comprises a plurality of domains comprising thermally-stable refined precipitates distributed in a matrix, wherein the matrix undergoes static recrystallization during the treating to form refined grains, while static crystallization in the plurality of domains is minimized or prevented. ### Claim 14 (depends on 10) The method of claim 10, further comprising a heat treatment after the subjecting in an environment having a temperature of greater than or equal to about 150° C. to less than or equal to about 300° C. for a duration of greater than or equal to about 2 hours to less than or equal to about 100 hours to enhance mechanical properties of the magnesium-based alloy component. ### Claim 15 (depends on 10) The method of claim 10, wherein after the annealing, the preform comprises one or more intermetallic species selected from the group consisting of: ZnZr, AlMn, MnSc, AlRE, where RE is a rare earth element, and combinations thereof. ### Claim 16 (depends on 10) The method of claim 10, wherein the magnesium-based alloy component is an automotive component selected from the group consisting of: an internal combustion engine component, a valve, a piston, a turbocharger component, a rim, a wheel, a ring, and combinations thereof. ### Claim 17 A solid magnesium-based alloy component comprising a microstructure with greater than or equal to about 5% by area to less than or equal to about 50% by area of elongated thermally stable grains comprising an intermetallic species having an average size of greater than or equal to about 1 nm to less than or equal to about 1 μm distributed in a matrix comprising dynamically recrystallized grains having an average size of greater than or equal to about 0.1 μm to less than or equal to about 20 μm, wherein the solid magnesium-based alloy component is substantially free of cracking. ### Claim 18 (depends on 17) The solid magnesium-based alloy component of claim 17, where the microstructure is formed from a magnesium-based alloy comprising zirconium at greater than or equal to 0 to less than or equal to about 1 wt. %; manganese at greater than or equal to about 0.3 wt. % to less than or equal to about 2 wt. %; scandium at greater than or equal to 0 to less than or equal to about 15 wt. %; a rare earth metal element at greater than or equal to 0 to less than or equal to about 20 wt. %; zinc at greater than or equal to 0 to less than or equal to about 6 wt. %; aluminum at greater than or equal to 0 to less than or equal to about 3 wt. %; and a balance of magnesium. ### Claim 19 (depends on 18) The solid magnesium-based alloy component of claim 18, where the intermetallic species is selected from the group consisting of: ZnZr, AlMn, MnSc, AlRE, where RE is a rare earth element, and combinations thereof. ### Claim 20 (depends on 17) The solid magnesium-based alloy component of claim 17, wherein the solid magnesium-based alloy component is an automotive component selected from the group consisting of: an internal combustion engine component, a valve, a piston, a turbocharger component, a rim, a wheel, a ring and combinations thereof.