AZ31 Magnesium Alloy Bending-rolling Flat Composite Deformation Process And Performance Research

The density of magnesium alloy is the lowest among all structural materials.Its application in the transportation industry will greatly reduce the transportation cost,and magnesium alloy has a high recycling rate.Therefore,the use of magnesium alloy is conducive to environmental protection,and is called "green engineering materials".However,due to its unique crystal arrangement type,magnesium alloy has a lower plastic forming limit at room temperature,which leads to its application scope less than aluminum,iron and other common metals.Therefore,if the application of magnesium alloys is expanded,the first problem to be solved is to improve the plastic deformation ability of magnesium alloys.In this paper,the material flow law of AZ31 magnesium alloy sheet in the combined deformation of bending and rolling under different processes was studied by numerical simulation and experiment,and the effects of different process parameters on the microstructure,mechanical properties and texture of magnesium alloy sheet were analyzed.The following conclusions are obtained:(1)The bending rolling compound deformation process of AZ31 magnesium alloy sheet was numerically simulated,and the variation laws of stress field,failure coefficient and temperature field during the compound deformation process were analyzed.The die structure and process parameters were optimized.(2)After the process parameters are determined,the AZ31 magnesium alloy plate is subjected to the combined deformation of bending and rolling by different processes.After the combined deformation by different processes,the plate surface is free of cracks,wrinkles and other defects.(3)The influence of composite deformation under different processes on the microstructure of AZ31 magnesium alloy sheet was analyzed.The results showed that the maximum grain refinement of single pass composite deformation was 36.6%,and that of double pass composite deformation was 56.8%.(4)The mechanical properties and texture of the composite deformed plate were tested.The results show that the tensile strength and elongation of the sheet after two passes of combined deformation increase by 20.5% and 12.0% respectively;After two passes of combined deformation,the maximum weakening degree of {0001} basal texture of the sheet is 48.8%.(5)The cellular automata(CA)method was used to simulate the microstructure of magnesium alloy plate during the combined bending rolling deformation process.Dynamic recrystallization occurred in the plate after the combined deformation,and the grains were refined.The average grain size obtained by simulation was consistent with the actual results,with the maximum error of 7.34%.