High-strength high-toughness AZ91 magnesium alloy strip eletrotoughening process method and system

Abstract

The invention discloses an electro-strengthening and toughening processing method of a belt material of AZ91 magnesium alloy and a system thereof. The electro-strengthening and toughening processing method comprises following steps: when the belt material of magnesium alloy is transmitted at a certain speed which is driven by a roller on an electro plastic rolling machine, high-energy impulse current that is output by an impulse power source through an electrode is input into an electriferous region section of the moving belt material of magnesium alloy, and the Joule heating effect and the non-heating effect are generated in the electriferous region section, thus causing the phase transition of internal microscopic constitution from bulky lath-shaped Beta-Mg17Al12 that are gathering and agglomerating in an initial state to Beta-Mg17Al12 particles that are evenly distributed and approximately sphere-shaped, or causing the solid solution effect that leads Beta-Mg17Al12 to be dissolved in a substrate; the processed belt material can be naturally air cooled at room temperature. The electro-strengthening and toughening processing method of the belt material of AZ91 magnesium alloy has short processing time and high production efficiency, and simultaneously avoids the high-temperature oxidation of the magnesium alloy. After the electro-strengthening and toughening processing, the microscopic constitution of the belt material of magnesium alloy can be remarkably improved, the unit extension of the microscopic constitution is increased from 11.8 percent in the initial aging state to over 20 percent, and the tensile strength of the microscopic constitution is not dramatically lowered.

Description

technical field [0001] The invention relates to a toughening treatment technology for magnesium alloy strips, in particular to an electro-induced toughening treatment process and a treatment system for high-strength and high-toughness AZ91 magnesium alloy strips. Through the electro-induced toughening treatment process, high Strength and high toughness AZ91 magnesium alloy strip. Background technique [0002] With the global energy crisis and environmental pollution becoming more and more serious, in order to reduce energy consumption and reduce environmental pollution caused by automobile exhaust emissions, the lightweight of automobiles has become the trend of the world's major automobile manufacturers to develop high-end and practical automobile products. It has become inevitable to use magnesium alloy instead of aluminum alloy or even steel material for automobiles to reduce the weight of automobiles. In particular, magnesium alloy, as the lightest engineering metal str...

AI Technical Summary

Problems solved by technology

In the AZ91 magnesium alloy with this structure, the coarse lath-like β-Mg at the grain boundary is formed during subsequent deformation or in the process of bearing external loads 17 Al 12 and flakes of β-Mg 17 Al 12 Stress concentration is easy to occur at the group, forming a crack source and causing cracks, which makes the material fail prematurely and is not conducive to subsequent molding, so β-Mg 17 Al 12 The quantity, distribution and morphology characteristics of AZ91 magnesium alloy seriously affect the mechanical properties

Obviously, if the toughness and subsequent forming ability of AZ91 magnesium alloy are to be further improved on this basis, the only way to improve the β-Mg 17 Al 12 The distribution and morphology make it develop in the direction that is conducive to the improvement of its toughness, and the traditional solution heat treatment process can improve the plasticity of AZ91 magnesium alloy to a certain extent, but due to the large amount of β-Mg 17 Al 12 dissolves into the magnesium matrix and severely reduces its strength

In addition, due to the slow diffusion rate of solute atoms in the solid phase in magnesium alloys, the solution treatment process of general magnesium alloys has high heating temperature (above 410°C) and long holding time (depending on the batch size in the furnace, generally a few Hours) and high energy consumption, due to high heating temperature and long holding time, the surface of magnesium alloys is easy to oxidize, especially once local surface oxidation occurs on magnesium alloy plates and strips, it is difficult to remove the oxide layer after subsequent treatment, seriously It affects the quality of the subsequent molding process and the final product; at the same time, under the condition of high temperature for a long time, the AZ91 magnesium alloy is prone to abnormal grain growth, which directly leads to serious uneven grain size inside the material and seriously damages the final mechanical properties of the material

Furthermore, the heating method and heating speed of the magnesium alloy must be strictly controlled to prevent that once the heating method and heating speed are selected improperly, the internal temperature of the material will be uneven and local overburning will eventually lead to the internal corrosion of the material after solution treatment. The consequences of uneven structure and unstable mechanical properties, so the factors affecting the traditional heat treatment process are complicated and the production cost is high

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