# US 2020/0399741 A1 · Magnesium alloy and preparation method thereof

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- Number: US 2020/0399741 A1
- Document ID: US20200399741A1
- Status: Published application
- Kind: A1
- Application number: 16/550,772
- Filed: 2019-08-26
- Published: 2020-12-24
- Earliest claimed: 2019-06-21
- Assignees: CITIC Dicastal Co., Ltd.
- Applicants: CITIC Dicastal CO., LTD.
- Inventors: Chunhai Liu; Lixin Huang; Yongfei Li; Long Zhai; Kedi Ding; Liguo Yang
- Web page: https://patentgrep.com/patent/US20200399741A1

## CPC

- C22C 23/02: with aluminium as the next major constituent
- B22D 7/005: {from non-ferrous metals}
- B22D 11/001: {of specific alloys}
- C22C 1/02: by melting {(C22C1/1036 takes precedence)}
- C22F 1/06: of magnesium or alloys based thereon
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- B22D: CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES (shaping of plastics or substances in a plastic state B29C; metallurgical processing, selection of substances to be added to metal C21, C22)
- 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

The present disclosure provides a magnesium alloy and a preparation method thereof. The magnesium alloy comprises: Al: 7.01-9.98 wt %; Zn: 0.1-1.2 wt %; Mn: 0.05-0.2 wt %; Sn: 0.3-2.5 wt %; Sm: 0.1-0.5 wt %; and a balance of Mg.

## Claims

### Claim 1

A magnesium alloy, comprising:
Al: 7.01-9.98 wt %; Zn: 0.1-1.2 wt %; Mn: 0.05-0.2 wt %; Sn: 0.3-2.5 wt %; Sm: 0.1-0.5 wt %; and a balance of Mg.

### Claim 2 (depends on 1)

The magnesium alloy according to claim 1, wherein the magnesium alloy further comprises Y: 0.05-0.1 wt %.

### Claim 3 (depends on 2)

The magnesium alloy according to claim 2, wherein the magnesium alloy further comprises Ca: 0.05-0.2 wt %.

### Claim 4

A preparation method of a magnesium alloy comprising Al: 7.01-9.98 wt %; Zn: 0.1-1.2 wt %; Mn: 0.05-0.2 wt %; Sn: 0.3-2.5 wt %; Sm: 0.1-0.5 wt %; and a balance of Mg, comprising:
heating a solid raw material of Mg to 700-730° C. for melting to form a Mg melt;
heating solid raw materials of rest ingredients to preset temperatures of the ingredients, then adding the Mg melt for melting, and stirring for a preset time to form a mixed melt; and
solidifying the mixed melt to form the magnesium alloy.

### Claim 5 (depends on 4)

The method according to claim 4, wherein the step of heating solid raw materials of rest ingredients to preset temperatures of the ingredients, then adding the Mg melt for melting, and stirring for a preset time to form the mixed melt comprises:
separately heating solid raw materials of Sn and Zn to 50-100° C., heating solid raw materials of Al, Mn, Sm, Y and Ca to 150-250° C.,
adding the Mg melt,
raising a temperature of the Mg melt by 20-40° C.,
maintaining the raised temperature for 5-15 minutes, and then
stirring for 3-10 minutes to form the mixed melt.

### Claim 6 (depends on 5)

The method according to claim 5, wherein after the step of heating solid raw materials of rest ingredients to preset temperatures of the ingredients, then adding the Mg melt for melting, and stirring for a preset time to form the mixed melt and before the step of solidifying the mixed melt to form the magnesium alloy, the method further comprises:
lowering the temperature of the mixed melt by 20-40° C. for refining degassing treatment, and then
maintaining the lowered temperature for 3-15 minutes for standing treatment.

### Claim 7 (depends on 6)

The method according to claim 6, wherein forming the mixed melt through heating all the ingredients in sequence for melting all the ingredients is performed under the protection of CO2/SF6 mixed gas.

### Claim 8 (depends on 7)

The method according to claim 7, wherein the step of solidifying the mixed melt to form the magnesium alloy comprises:
removing dross on a surface of the mixed melt, and then preparing a magnesium alloy ingot by gravity casting or semicontinuous casting.

### Claim 9 (depends on 8)

The method according to claim 8, wherein after the step of removing dross on a surface of the mixed melt, and then preparing a magnesium alloy ingot by gravity casting or semicontinuous casting, the method further comprises:
performing solid solution treatment on the magnesium alloy ingot, wherein the solid solution treatment comprises:
performing solid solution treatment for 7-24 hours at a temperature of 380-430° C., and then quenching with warm water with a temperature of 40-80° C.

### Claim 10 (depends on 9)

The method according to claim 9, wherein after the step of performing solid solution treatment on the magnesium alloy ingot, the method further comprises:
performing aging treatment on the magnesium alloy ingot, wherein the aging treatment comprises:
firstly maintaining a temperature of 300-350° C. for 0.5-2 h, then maintaining a temperature of 150-200° C. for 8-15 h, and finally cooling to room temperature.