ULTRAFINE-GRAINED PROFILE OF TWIN-CRYSTAL WROUGHT MAGNESIUM ALLOYS, PREPARATION PROCESS AND USE OF THE SAME

摘要

The present invention provides an ultrafine-grained profile of twin-crystal wrought magnesium alloys, preparation process and use of the same. In the process, raw materials of magnesium alloys are firstly smelted and cast, and are subjected to solution treatment at 300˜500° C.; then a preform is pre-deformed, so that a great amount of twin crystal microstructure forms in the magnesium alloys and the grain size of not larger than 100 μm is achieved; subsequently continuous ECAP process is performed at 200˜350° C., and the die is replaced in according to requirement so as to obtain the desired profile. The ultrafine-grained profile of magnesium alloys prepared in the invention has the grain sizes of from 100 to 450 nm, the tensile strength of 300˜400 MPa, and the elongation of 20˜35%. The length of the profile can be more than 10 m, meeting the needs of continuous production.

主权项

1. A process for preparing ultrafine-grained profile of twin-crystal wrought magnesium alloys, which comprises the steps as follows:
(1) subjecting raw materials of magnesium alloys to smelting and casting under the atmospheric protection, and solid solution at 300˜500; (2) subjecting a preform obtained from step (1) to pre-deformation, so that a great amount of twin crystal microstructure forms in the magnesium alloys and the grain size of not larger than 100 μm is achieved; (3) conducting continuous Equal Channel Angular Pressing process below the re-crystallization temperature, wherein the channel angle is 90°˜120°, the linear pressing speed is not beyond 10 mm/s, the strain rate in the last pass is about 60˜340%, and the die can be replaced in the last pass of the pressing according to requirement so as to obtain the desired profile; and (4) annealing the profile at 150˜300.