Method for purifying non-metal inclusion in magnesium alloy by ultrasonic agglomeration

Abstract

The invention discloses a method for purifying non-metallic inclusions in the magnesium alloy through ultrasonic coagulation, and belongs to the field of material science. The method comprises the following steps: placing a magnesium alloy casting blank into a crucible, heating up the casting blank to 50 to 120 DEG C above a liquidus line under the conditions of protective atmosphere and stirringso as to turn the magnesium alloy casing blank into magnesium alloy fused mass; applying ultrasonic waves to the magnesium alloy fused mass with the ultrasonic wave frequency of 18 to 22kHz, the ultrasonic wave strength of 0.1 to 6.0W / cm<2>, and the time of 10 to 80s; and shifting out an ultrasonic wave rod after the application of the ultrasonic waves is finished, and cooling down the magnesium alloy fused mass to room temperature. After the low-strength ultrasonic wave treatment of the magnesium alloy fused mass is finished, the sedimentation rate of the inclusions in the magnesium alloy casting blank can be remarkably improved so as to realize the purification effects; and the area fraction of the inclusions can be reduced by 50 to 90 percent.

Description

technical field [0001] The invention belongs to the field of material science, and particularly relates to a method for ultrasonic coagulation and purification of non-metallic inclusions in magnesium alloys. Background technique [0002] Many advantages such as low density, high specific strength and high specific rigidity make magnesium alloys more and more widely used in the aerospace industry, military industry, transportation, and 3C fields, but the main problems in the application of magnesium alloys include poor corrosion resistance. , poor plastic deformation performance and low strength, which are directly or indirectly related to the low purity of magnesium alloy melt. Magnesium alloy melt is easily oxidized and combustible in the process of smelting and casting, and a large number of non-metallic compounds produced by it are difficult to separate well from magnesium alloy melt. Poor purity of magnesium alloy melt limits the service performance and application field...

AI Technical Summary

Problems solved by technology

The problem with this method is that the main component of the flux MgCl 2 The density of magnesium is very similar to the density of molten magnesium. If the amount of flux or the refining temperature is not appropriate, the formation of flux inclusions may increase, and the flux refining operation time is long (30-40min), and the refined melt also needs to stand for a long time Operation, generally 1m deep melt needs to stand for 1h, the production efficiency is very low

Physical filtration refining is a method of purifying magnesium melt by using steel mesh (or steel wool) or foam ceramic filter inert to magnesium melt; the former is an alternative economical and feasible purification method, but it is difficult to remove fine particles. inclusions; the problem with the latter is that it is difficult to find foamed ceramic materials that are durable to magnesium melts, so they have not been used industrially

However, for a long time, this problem has not been fully and clearly understood. In the early 1990s, the research work of some scholars in Japan and China further showed that it is feasible to use ultrasound to form standing waves to realize the condensation and separation of solid inclusions in metallurgical melts.

However, relevant research is limited to theoretical analysis and physical simulation, and has not been verified by actual treatment of metallurgical melts, and there are no examples of industrial applications.

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