AZ31镁合金板材纵波轧制形变规律及边部损伤分析

Analysis on Deformation Law and edge damage of AZ31 Magnesium Alloy Sheet in Longitudinal Wave Rolling

摘要:

纵波轧制+平辊轧制(LFR)是一种减轻镁合金轧制边裂的新型轧制工艺，通过一道次纵波轧制+二道次平轧，可有效减少镁合金板材边裂。为了进一步明晰LFR变形规律，本文通过对比AZ31镁合金板材纵波轧制+平轧(LFR)及平轧+平轧(FFR)热-力耦合有限元虚拟轧制对比和物理实验，分析了纵波轧制变形区金属变形规律及其对板材边部损伤的影响。结果表明：纵波轧制形成了异形搓轧区，板材各部位受到较大的三向剪切作用；急速金属流动产生的塑性变形热避免了板材边部温降，有利于提升塑性；剪切及温度影响促使LFR板材形成混晶组织，降低了波谷部位损伤，进而有效抑制了镁合金板材边裂的产生及发展。

Abstract:

Longitudinal wave rolling + flat roll rolling ( LFR ) is a new rolling process to reduce edge cracks and basal texture of magnesium alloy. This process can prepare magnesium alloy sheets with light edge cracks through one-pass longitudinal wave rolling + two-pass flat rolling. However, the LFR process deformation law is not clear. In this paper, the thermo-mechanical coupling finite element virtual rolling comparison and physical experiments of AZ31 plate longitudinal wave rolling + flat rolling ( LFR ) and flat rolling + flat rolling ( FFR ) were compared, the metal deformation law in the longitudinal wave rolling deformation zone and its influence on the edge damage of the plate were analyzed. The results show that a special-shaped rolling area has formed in the longitudinal wave rolling, which caused shear strain in different parts of the sheet. Furthermore, the temperature drop at the edge of the plate was avoided due to the plastic deformation heat generated by rapid metal flow, which is beneficial to improve the plasticity. The influence of shear strain and temperature promotes the formation of mixed microstructure of LFR sheet, reduces the damage of trough, and effectively inhibits the generation and development of edge crack of magnesium alloy sheet.