Production and apparatus for preparing non-dendritic and semi-solid alloy by low-voltage pulse electric field

A pulsed electric field and semi-solid technology, which is applied in the field of semi-solid metal processing, can solve the problems of stirring dead angle, difficult operation, poor safety performance, etc., so as to avoid air suction and slag inclusion, stabilize the melt liquid cavity, and improve product quality Effect

Inactive Publication Date: 2009-08-26
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The mechanical stirring method has the following disadvantages: (1) the life of the stirring chamber and the stirring rod is not long, the metal is more prone to oxidation and pollution, and the internal quality of the metal is very low; (2) there is a dead angle of stirring, which affects the uniformity of the slurry; (3) the equipment Bulky, difficult to operate, low production efficiency, the solid phase fraction can only be limited in the range of 30% to 60%
However, the electrical pulses they use are high or ultra-high voltage, generally from several thousand volts to tens of thousands of volts, such a high voltage brings great inconvenience to the operator, and the safety performance is relatively poor; and in the pulse discharge In the experiment, the metal or alloy is cooled naturally in the air or cooled with the furnace, the controllable time of the solidification process is short, and the control effect of the pulse electric field on the solidification structure cannot be fully exerted.
More importantly, none of them used electrical pulses to produce non-dendritic spherical semi-solid alloys

Method used

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  • Production and apparatus for preparing non-dendritic and semi-solid alloy by low-voltage pulse electric field
  • Production and apparatus for preparing non-dendritic and semi-solid alloy by low-voltage pulse electric field
  • Production and apparatus for preparing non-dendritic and semi-solid alloy by low-voltage pulse electric field

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] The Al-4.5% Cu alloy is melted and refined in a heat preservation crucible, and kept at 675° C. for 30 minutes to ensure that the temperature of the alloy liquid is uniform, and the electrode and the alloy melt are well connected. When the temperature of the alloy melt drops to 651°C, start the pulse generating device and begin to discharge the alloy melt. The discharge voltage is 300V, the discharge time is 10 minutes, and the pulse frequency is 0.13Hz. The average cooling of the alloy during the pulse discharge process The speed is controlled at 2°C / min, and the upper electrode is removed after the discharge, and the alloy ingot is cooled with the furnace. It can be seen from Figure 2(a) and Figure 2(b) that the microstructure of the ingot after the low-voltage pulsed electric field treatment changes from the original coarse dendrite to the spherical or granular non-dendritic structure.

[0049] Additionally, if image 3 As shown, the pulse electric field generating ...

Embodiment 2

[0055] The AZ91D alloy is melted and refined in a heat preservation crucible, and kept at 650°C for 20 minutes to ensure that the temperature of the alloy liquid is uniform, and the electrode is connected to the alloy melt. When the temperature of the alloy melt drops to 593°C, start the pulse generating device and begin to discharge the alloy melt. The discharge voltage is 400V, the discharge time is 20 minutes, and the pulse frequency is 0.125Hz. The average cooling of the alloy during the pulse discharge process The speed is controlled at 15°C / min, and the upper electrode is removed after the discharge, and the alloy ingot is cooled with the furnace.

Embodiment 3

[0057]Melt and refine pure aluminum in an insulated crucible, keep it at 700°C for 40 minutes to ensure uniform temperature of the alloy liquid, and connect the electrodes to the alloy melt. When the temperature of the alloy melt drops to 670°C, start the pulse generating device and begin to discharge the alloy melt. The discharge voltage is 350V, the discharge time is 15 minutes, and the pulse frequency is 0.5Hz. The average cooling of the alloy during the pulse discharge process The speed is controlled at 28°C / min. After the discharge, the upper electrode is removed, and the alloy ingot is cooled with the furnace.

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Abstract

The invention relates to a low-voltage pulse electric field preparation method and special equipment for semi-solid metal slurry or blank. Preparation method: first melt the alloy and keep it warm in the heat preservation crucible. The upper and lower ends of the alloy melt are respectively connected to the positive and negative electrodes of the output end of the pulse power supply. Before the solidification starts, start the pulse power supply to perform pulse discharge on the alloy melt. Apply a pulsed electric field. Special equipment: It consists of three parts: pulse electric field generator, pulse electric field effect device and heating and heat preservation device. The pulse current generated by the pulse electric field generator is applied to the alloy melt placed in the heat preservation device through the pulse electric field effect device. Adjust the pulse discharge voltage, discharge time and pulse frequency according to the type and composition of the alloy, and control the solidification speed of the alloy during the pulse discharge, and finally obtain a non-dendritic semi-solid alloy blank or slurry with a spherical or granular primary phase , can be used in the production of metal semi-solid alloy preparation and forming.

Description

technical field [0001] The invention belongs to the technical field of semi-solid metal processing, and in particular relates to a method and equipment for preparing non-dendritic semi-solid alloys using a low-voltage pulse electric field from semi-solid metal slurry or blanks. Background technique [0002] Since American scientists first proposed the concept of metal semi-solid forming in the 1970s, semi-solid metal processing technology has attracted extensive attention from the international materials community and has become one of the most active research fields today. This method can not only reduce costs, improve casting quality and yield, but also has the advantages of high efficiency, energy saving and environmental protection. At present, some developed countries have begun to apply it in the fields of automobile manufacturing, communications, electrical appliances, computers and their auxiliary equipment, aerospace and other fields, and have broad development pros...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22D27/02
Inventor 杨院生周全
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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