A method for crushing and spheroidizing the second phase in magnesium alloy by heating and rotating rolling

Abstract

The invention relates to the field of metal material rolling processing and particularly discloses a method for carrying out warming, rotary rolling, fragmentation and spheroidization on a second phase in magnesium alloy. The method comprises the following steps: S1, carrying out earlier stage thermal insulating treatment; S2, carrying out single-pass fragmentation on the second phase; and S3, carrying out warming and rotary rolling on the second phase. According to the method, warming four-pass rotary rolling is utilized, and clockwise 90-degree rotation is realized each pass, so that the situation that the second phase is cured in a multidirectional manner is ensured, and submicron order second phase also can separate out dynamically; and in addition, high-density dislocation is introduced during first-pass low temperature rolling to promote dynamic recrystallization and realize the purpose of refining grain during the following warming rolling process; and moreover, the submicron order second phase and fine grain structures improve the strengthening and processing hardening capacity and improve the strength and plasticity simultaneously.

Description

technical field [0001] The invention relates to the field of rolling processing of metal materials, in particular to a method for crushing and spheroidizing the second phase in a magnesium alloy by temperature-rising rotary rolling. Background technique [0002] As the lightest structural material currently available, magnesium has great application value and broad prospects in light weight. The mechanical properties of magnesium alloys are closely related to the second phase, texture, grain size and other factors. Improving the shape, size and distribution of the second phase will greatly increase the tensile strength and elongation of magnesium alloys. However, as-cast magnesium alloys will inevitably produce a large number of dendrites and coarse eutectic phases, and in the composition design process of magnesium alloys, some elements will form large-sized second phases (tin, calcium, zinc, etc.) after combination, even It is also difficult to eliminate after high temper...

AI Technical Summary

Problems solved by technology

However, as-cast magnesium alloys will inevitably produce a large number of dendrites and coarse eutectic phases, and in the composition design process of magnesium alloys, some elements will form large-sized second phases (tin, calcium, zinc, etc.) after combination, even Difficult to remove after high temperature heat treatment

[0003] Calcium can play the role of flame retardancy, so it is especially suitable for large-scale smelting production, but when calcium is added together with some alloying elements, due to its low solid solubility, a coarse second phase will be produced in the matrix, It needs solid solution at high temperature and long time in protective gas, which leads to higher production cost and limits its industrial application

[0004] It is generally believed that the large-sized second phase in the magnesium alloy will split the matrix during the deformation process, leading to early initiation of cracks, thereby reducing the plasticity.

At present, the methods of crushing the second phase include extrusion at a slow speed and large extrusion ratio, and large deformation such as equal-diameter angular extrusion. The above-mentioned methods are currently limited to the stage of preparing small samples in the laboratory, and cannot be mass-produced industrially. Improving the Comprehensive Mechanical Properties of Magnesium Alloys

Images