A kind of deformation heat treatment method of mg-al system precipitation strengthened magnesium alloy

Abstract

The invention belongs to the technical field of metal strengthening and toughening and relates to a thermomechanical treatment method to acquire Mg17Al12 continuous precipitate of large volume fraction and high dispersity from precipitation-hardened Mg-Al alloys. According to the method, massive high-deformation energy storage areas are formed in a material through plastic deformation to further promote continuous precipitation; high-deformation energy storage areas capable of promoting continuous precipitation in Mg-Al precipitation-hardened alloys are mainly twin areas, so that a deformationpath most helpful for increasing twin area volume fractions is selected for performing deformation; by optimizing the parameters, such as the deformation path, strain capacity and aging system, Mg17Al12 continuous precipitate of high volume fraction and high dispersity is acquired and aging strengthening effect is thus improved.

Description

technical field [0001] The invention belongs to the technical field of metal strengthening and toughening, and in particular relates to a deformation heat treatment method of a Mg-Al series precipitation strengthening type magnesium alloy. Background technique [0002] Mg-Al series precipitation-strengthened alloy is a low-cost high-strength magnesium alloy. The alloy system uses Al as the main alloying element with a content greater than 5wt.%. Because the melting process of this type of alloy is simple and the metallurgical quality is easy to control, it is very It is suitable for the preparation of die-casting products and large-scale deformed magnesium alloy components, which are widely used in aviation, automobile and 3C product fields, such as vehicle hubs, helicopter receivers, aircraft load-bearing structural parts, etc. The strengthening method of this alloy system is mainly aging heat treatment, but its aging strengthening effect is poor, because Mg 17 al 12 The ...

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Problems solved by technology

During the deformation process, steel and aluminum alloys are dominated by slip, and deformation twins are not common, while magnesium alloys have less slip systems, and twins account for a large proportion. When the temperature is lower than 225 °C, the plastic deformation of polycrystalline magnesium alloys is only Limited to the basal plane {0001} slip and {10-12} tensile twinning, at the same time, the distribution of dislocations and twinning is difficult to control; in addition, wrought magnesium alloys usually have strong texture, so the anisotropy is very significant, and different deformation paths often correspond to different plastic deformation mechanisms, so it is difficult to choose the deformation path; secondly, for the commercial Mg-Al alloys with the largest amount at present, the study found that the plastic deformation Can promote high dispersion of nano-sized Mg 17 al 12 Continuous phase precipitation, but the selection of relevant deformation parameters has not been fully studied; these pose challenges for the application of thermomechanical treatment in magnesium alloys

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