Zirconium refinement method for magnesium alloy crystalline grains

A technology of magnesium alloy and magnesium-zirconium master alloy, which is applied in the refinement process of magnesium alloy solidification structure, can solve the problems of rare metal Zr waste, increase alloy casting cost, and easy precipitation specific gravity, etc., and achieve high yield of zirconium element, The effect of reducing the loss of zirconium and uniform distribution of the structure

Active Publication Date: 2015-09-23
SHANGHAI JIAO TONG UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the production method of this magnesium-zirconium master alloy needs to evacuate the reduction furnace and add inert gas, the quality is difficult to control, and the alloy impurities are high; at the same time, the as-cast magnesium-zirconium master alloy has coarse grains and uneven distribution of zirconium. It is solid when added to magnesium alloy, and it is difficult to dissolve, and zirconium is unevenly distributed in magnesium alloy, and the refining effect is poor; in addition, the specific gravity difference with magnesium liquid is large, and it is easy to precipitate or form specific gravity segregation
The existence of the above problems leads to the waste of a large amount of rare metal Zr in actual production, which increases the cost of alloy casting and becomes a bottleneck for obtaining a stable grain refinement effect.

Method used

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  • Zirconium refinement method for magnesium alloy crystalline grains
  • Zirconium refinement method for magnesium alloy crystalline grains
  • Zirconium refinement method for magnesium alloy crystalline grains

Examples

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Comparison scheme
Effect test

Embodiment 1

[0028] Step 1, preparation of magnesium-zirconium master alloy: (a) preheat potassium zirconium fluoride and magnesium ingot at 150°C for 40 minutes to remove free water; (b) pre-dry potassium fluoride zirconate and magnesium The ingot is placed in a stainless steel crucible in a temperature-controlled and heat-preserving overturning furnace for reduction reaction. Under the protection of the mixed molten salt system of NaCl and KCl, one-step reduction forming produces a magnesium-zirconium master alloy ingot with a zirconium content of 15wt.%. Magnesium ingot: The dosage ratio of potassium zirconium fluoride: NaCl: KCl is 1:1:0.5:0.5; the reduction temperature is 900°C, and the reduction time is 35 minutes; after the reduction reaction is completed, the reactant is controlled to form, and the casting speed of the electromagnetic vibration casting mold system is 10kg / min, the casting temperature is 1040°C, the electromagnetic vibration frequency is 200Hz, and the time is 4min;...

Embodiment 2

[0031]Step 1, preparation of magnesium-zirconium master alloy: (a) preheat potassium zirconium fluoride and magnesium ingot at 150°C for 40 minutes to remove free water; (b) pre-dry potassium fluoride zirconate and magnesium The ingot is placed in a stainless steel crucible in a temperature-controlled and heat-preserving overturning furnace for reduction reaction. Under the protection of the mixed molten salt system of NaCl and KCl, one-step reduction forming produces a magnesium-zirconium master alloy ingot with a zirconium content of 40wt.%. Magnesium ingot: The dosage ratio of potassium zirconium fluoride: NaCl: KCl is 1:1.8:1.5:1.5; the reduction temperature is 1300°C, and the reduction time is 45 minutes; after the reduction reaction is completed, the reactant is controlled to form, and the casting speed of the electromagnetic vibration casting mold system is 15kg / min, the casting temperature is 1070°C, the electromagnetic vibration frequency is 400Hz, and the time is 5mi...

Embodiment 3

[0034] Step 1, preparation of magnesium-zirconium master alloy: (a) preheat potassium zirconium fluoride and magnesium ingot at 150°C for 40 minutes to remove free water; (b) pre-dry potassium fluoride zirconate and magnesium The ingot is placed in a stainless steel crucible in a temperature-controlled and heat-retaining turning furnace for reduction reaction. Under the protection of the mixed molten salt system of NaCl and KCl, one-step reduction forming produces a magnesium-zirconium master alloy ingot with a zirconium content of 30wt.%. Magnesium ingot: The dosage ratio of potassium zirconium fluoride: NaCl: KCl is 1:1:1:1; the reduction temperature is 1100°C, and the reduction time is 40 minutes; after the reduction reaction is completed, the reactant is controlled to form, and the casting speed of the electromagnetic vibration casting mold system is 10kg / min, the casting temperature is 1050°C, the electromagnetic vibration frequency is 300Hz, and the time is 4.5min; (c) u...

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Abstract

The invention provides a zirconium refinement method for magnesium alloy crystalline grains. The method includes the following steps that a, after potassium fluozirconate and a magnesium ingot are dried, under protection of a mixed fused salt system including NaCl and KCl, the potassium fluozirconate and the magnesium ingot are subjected to a reduction reaction for 35-45 min at the temperature of 900-1300 DEG C, casting is carried out for 4-5 min at the casting speed of 10-15kg / min at the temperature of 1040-1070 DEG C at the electromagnetic vibration frequency of 200-400 Hz, and a magnesia-zirconia master alloy ingot is obtained; b, pre-deformation treatment is carried out on the magnesia-zirconia master alloy ingot to obtain a magnesia-zirconia master alloy refiner; c, after a magnesium alloy raw material is smelted, the magnesia-zirconia master alloy refiner is added at the temperature of 750-780 DEG C, and after surface dross is removed, stirring, drossing and peeling are carried out. Compared with the prior art, the adopted refiner is magnesia-zirconia master alloy subjected to pre-deformation treatment, zirconium particles are fine and evenly distributed, the refining effect is good, a magnesium alloy structure is evenly distributed, the quality of a magnesium alloy product is improved, and the method is suitable for experimental and industrial application.

Description

technical field [0001] The invention relates to a process method for refining the solidification structure of a magnesium alloy, in particular to a method for refining the grain zirconium of a magnesium alloy. Background technique [0002] Magnesium alloy is currently the lightest metal structural material in practical application. It has the advantages of low density, high specific strength and specific stiffness, good damping and shock absorption, good thermal conductivity, and excellent machining performance. It is used in automobiles, national defense, aviation, Aerospace, electronics and other industrial fields have very broad application prospects. Magnesium is one of the most abundant elements on the earth, and my country is a big producer of magnesium resources and magnesium alloys, accounting for 40% of the global output. However, magnesium alloy has a hexagonal close-packed (HCP) crystal structure, and there are only three independent slip systems at room temperat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C1/06C22C1/03C22C23/00
Inventor 刘文才吴国华陈翔隽丁文江
Owner SHANGHAI JIAO TONG UNIV
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