Method for improving fatigue performance of rare earth magnesium alloy by utilizing abnormal twin crystals

A fatigue performance and rare earth magnesium technology, which is applied in the field of improving the fatigue performance of rare earth magnesium alloys, can solve the problems of increased production costs, heavier rare earth elements, and increased alloy density, and achieve low environmental protection costs, wide range of applicable materials, and improved fatigue performance Effect

Inactive Publication Date: 2017-09-22
CENT SOUTH UNIV
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Problems solved by technology

At the same time, the addition of heavy rare earth elements not o...

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  • Method for improving fatigue performance of rare earth magnesium alloy by utilizing abnormal twin crystals
  • Method for improving fatigue performance of rare earth magnesium alloy by utilizing abnormal twin crystals
  • Method for improving fatigue performance of rare earth magnesium alloy by utilizing abnormal twin crystals

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Embodiment 1

[0025] In this embodiment, the raw material is a Mg-1.5Gd alloy hot-rolled plate. After homogenizing annealing at 430℃ for 5h, the average grain size is about 120μm. The grain orientation is analyzed based on the electron backscattered diffraction technique, and the loading direction is selected according to the orientation distribution result. At 300°C, the specimen was pre-stretched along the direction of the angle 15-60° with the normal direction of the base surface, and the compression rate was 0.003s -1 , The strain is about 0.005-0.05.

[0026] The orientation distribution of the specimen after stretching is as follows: figure 1 As shown in (a), according to the criterion of abnormal twinning, the (0001) basal pole figure containing the twinned grain matrix is ​​drawn and its area is divided, where LD (Loading Direction) is the pre-deformed loading stress direction ( perpendicular to the direction of the paper), TD (Transverse Direction) is the transverse direction at...

Embodiment 2

[0029] The raw material used in this embodiment is the cast Mg-6Gd-3Y-1Zn-0.4Zr alloy. The average grain size is about 60 μm. At 25°C, 0.03s -1 Next, the specimen is pre-compressed along the angle 15-60° with the normal direction of the base surface, and the strain amount is about 0.01-0.03.

[0030] Based on the electron backscattered diffraction technique, the grain orientation of the stretched specimen was analyzed, and the orientation distribution was obtained image 3 (a), the (0001) basal pole figure containing the twinned grain matrix is ​​drawn and its area is divided. After compression along the LD direction (perpendicular to the paper surface) and pre-deformation treatment, 3 is the normal twinning area, 4 is the abnormal twin region, such as image 3 (b) shown. From image 3 (b) It can be seen that the angle between the loading direction and the normal direction of the (0001) basal plane of these grains is mainly concentrated at 15-60°, which meets the abnormal...

Embodiment 3

[0033] In this embodiment, the raw material is Mg-2Y magnesium alloy hot-rolled sheet, and after homogenizing annealing at 450° C. for 2 hours, the average grain size is about 120 μm. It was subjected to pre-bending treatment at 150°C. Due to the particularity of repeated bending deformation, the tissues on both sides of the neutral layer will be subjected to loads in two opposite directions during repeated bending. A suitable bending method should be selected to ensure that the grain basal plane is 15-60° to the loading direction, and the cumulative strain is about 0.002-0.04.

[0034] Orientation distribution of tissue after pre-deformation Figure 5 (a) Analysis and the (0001) basal pole figure containing twin grains Figure 5 (b) make and divide areas, Figure 5 In (b), 5 is the normal twinning region corresponding to stretching or compression along the LD direction (perpendicular to the paper surface) during repeated bending, and 6 is the abnormal twinning region. Dep...

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Abstract

The invention discloses a method for improving the fatigue performance of rare earth magnesium alloy by utilizing abnormal twin crystals. The method comprises the following steps: performing pre-deformation treatment on the rare earth magnesium alloy in the direction which forms an angle of 15 to 80 degrees with the normal direction of a base plane at 15 to 300 DEG C, wherein the true strain is 0.0005 to 0.1; arranging {10, 12} abnormal twin crystals in the rare earth magnesium alloy in advance through pre-deformation; performing fatigue test on the rare earth magnesium alloy with or without the abnormal twin crystals; compared with the rare earth magnesium alloy without the abnormal twin crystals, the fatigue limit of the rare earth magnesium alloy with the abnormal twin crystals is improved obviously; the fatigue life is prolonged; and the fatigue performance is obviously improved. The method is a process which is reasonable in design, simple in equipment requirement, convenient to operate, low in cost and high in efficiency and improves the fatigue performance of the rare earth magnesium alloy stably.

Description

technical field [0001] The invention relates to a method for improving the fatigue performance of rare earth magnesium alloys by using abnormal twins, in particular to a method for improving the fatigue performance of rare earth magnesium alloys through pre-deformation treatment and preset abnormal twins to control the structure, which belongs to non-ferrous metal material failure and protection technology areas. Background technique [0002] Rare earth magnesium alloys have broad application prospects in transportation, aerospace and other fields. It is gradually replacing aluminum alloy as a secondary load-bearing part or even a main load-bearing part for use in automobiles or aircraft. In recent years, although many countries and enterprises have invested heavily in the research and development of high-strength and tough rare earth magnesium alloy materials, compared with aluminum alloys, its industrial application process is still difficult to achieve the expected resul...

Claims

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Application Information

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IPC IPC(8): C22F1/06
CPCC22F1/06
Inventor 杨续跃肖振宇霍庆欢张笃秀
Owner CENT SOUTH UNIV
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