Heat treatment technology for improving mechanical properties of rare earth magnesium alloy castings

A technology of alloy castings and rare earth magnesium, which is applied in the field of magnesium alloys and heat treatment processes, can solve problems such as limitations and no substantial improvements, and achieve the effects of avoiding grain growth, high mechanical properties of alloys, and simple heat treatment processes

Active Publication Date: 2016-06-08
CENT SOUTH UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Although the degree of alloying of Mg-Y-Nd series magnesium alloys is relatively high, after the prior art adopts the T6 heat treatment process of solid solution + aging to heat treat the alloy, according to the literature (Zhang Na, Microstructure of Mg-Y-Nd alloy and performance research, Jilin University master's degree thesis, 2007) records, the alloy tensile strength index only reaches 275MPa, thus, limits the application of Mg-Y-Nd series magnesium alloys in many fields or working conditions, this field has long been It has been hoped to effectively improve the mechanical properties of Mg-Y-Nd series magnesium alloys, but so far, no substantial improvement has been achieved. Therefore, it is necessary to optimize the heat treatment process of Mg-Y-Nd magnesium alloys to meet the needs of different fields. Requirements for the mechanical properties of alloys

Method used

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  • Heat treatment technology for improving mechanical properties of rare earth magnesium alloy castings
  • Heat treatment technology for improving mechanical properties of rare earth magnesium alloy castings
  • Heat treatment technology for improving mechanical properties of rare earth magnesium alloy castings

Examples

Experimental program
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Effect test

Embodiment 1

[0047] The first step: adopt the method of low-pressure casting to prepare a kind of mass percentage of each element: Y3.8%; Nd2.5%; Zr0.45%; Gd0.3%; the total amount of other elements is less than 0.5%; the balance is Mg Large size Mg-Y-Nd alloy castings of Mg-Y-Nd. The wall thickness of the casting is 60mm at the thickest part, 30mm at the thinnest part, and the vertical projected area is greater than 0.5m 2 . The surface of the large-sized castings obtained by casting is ground to remove the sand and oxides on the surface, and cleaned with salt. Place the cleaned casting in the resistance and heat it up to 450°C with the furnace at a heating rate of 200°C / h and keep it warm for 15 to 16 hours, then raise the temperature to 545±5°C with the furnace at a heating rate of 50°C / h and keep it for 2~ After 3 hours, it is out of the furnace and air-cooled. Put the air-cooled parts in the resistance and heat up to 300°C with the furnace at a heating rate of 150°C / h. Heat up to 20...

Embodiment 2

[0049] The first step: adopt the method of low-pressure casting to prepare a kind of mass percentage of each element: Y3.5%; Nd2.6%; Zr0.5%; Gd0.35%; the total amount of other elements is less than 0.5%; the balance is Mg Large size Mg-Y-Nd alloy castings of Mg-Y-Nd. The wall thickness of the casting is 60mm at the thickest part, 30mm at the thinnest part, and the vertical projected area is greater than 0.5m 2 . The surface of the large-sized castings obtained by casting is ground to remove the sand and oxides on the surface, and cleaned with salt. Place the cleaned casting in the resistance and heat it up to 475°C with the furnace at a heating rate of 210°C / h and keep it warm for 15 to 16 hours, then raise the temperature to 545±5°C with the furnace at a heating rate of 75°C / h and keep it for 2~ After 3 hours, it is out of the furnace and air-cooled. Put the air-cooled parts in the resistance and heat up to 310°C with the furnace at a heating rate of 175°C / h. Heat up to 22...

Embodiment 3

[0051] The first step: adopt the low-pressure casting method to prepare a kind of mass percentage of each element: Y4.0%; Nd2.3%; Zr0.4%; Gd0.4%; the total amount of other elements is less than 0.5%; the balance is Mg Large size Mg-Y-Nd alloy castings of Mg-Y-Nd. The wall thickness of the casting is 60mm at the thickest part, 30mm at the thinnest part, and the vertical projected area is greater than 0.5m 2 . The surface of the large-sized castings obtained by casting is ground to remove the sand and oxides on the surface, and cleaned with salt. Place the cleaned casting in the resistance and heat it up to 480°C with the furnace at a heating rate of 220°C / h and keep it warm for 15-16 hours, then raise the temperature with the furnace to 545±5°C at a heating rate of 100°C / h and keep it for 2~ After 3 hours, it is out of the furnace, air-cooled, and the air-cooled parts are placed in the resistance and heated up to 320°C with the furnace at a heating rate of 200°C / h. Heat up t...

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Abstract

A heat treatment technology for improving mechanical properties of rare earth magnesium alloy castings is a heat treatment method which is used for carrying out staged solution and staged aging on Mg-Y-Nd magnesium alloy castings. Solution and aging are regarded as a whole body, namely, after being heated and subjected to primary solution and secondary solution sequentially, the castings are subjected to tertiary artificial aging sequentially, solution temperature, insulating time, aging temperature and insulating time are controlled, in a process of aging precipitation of strengthening phases containing Nd, a Y element is in a solution state, in a process of aging precipitation of a compound containing Y, a compound containing Nd cannot grow, the number of the strengthening phases subjected to aging precipitation is large, the strengthening phases are tiny, growth of crystal grains in a solution process is also avoided, and the mechanical properties of the alloys are improved. The heat treatment technology is simple, existing heat treatment equipment is not required to be modified, the mechanical properties of the obtained alloys are greater than those of alloys treated by a conventional method by at least 10%, industrial production is easy to implement, and a simple and efficient effective way is provided for improving the mechanical properties of the large-size rare earth magnesium alloy castings.

Description

technical field [0001] The invention relates to a preparation method of magnesium alloy castings, in particular to a heat treatment process of Mg-Y-Nd magnesium alloy castings; it belongs to the technical field of magnesium alloys and heat treatment processes. Background technique [0002] Mg-Y-Nd series magnesium alloys, as the most widely used rare earth magnesium alloys, are widely used in aviation, aerospace and other fields due to their excellent high-temperature mechanical properties. The alloy can be used to prepare various aviation components with large size and complex shape by low-pressure casting method. Due to the addition of Y and Nd elements in the alloy, Mg can be formed 41 Nd 5 , Mg 24 Y 5 and Mg 14 Nd 2 Y and other compounds, thus playing a strengthening role. However, these strengthening compounds need to be formed during the aging process, and the coarse compounds formed during the casting process cannot play a strengthening role, so when the alloy ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22F1/06C22C23/06
CPCC22C23/06C22F1/06
Inventor 李慧中赵俊刚梁霄鹏齐叶龙姚三成吕凤
Owner CENT SOUTH UNIV
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