Study On Microstructure And Mechanical Properties Of Mg-3Gd Alloy Prepared By High-throughput Rolling Process

In this paper,Mg-3Gd(wt.%)alloy was rolled by high-throughput rolling process.Magnesium alloy sheets with gradient structure and recrystallization texture were prepared.Samples were annealed at different temperatures for one hour to optimize the microstructure and properties.The effects of rolling and annealing treatment on the structure and properties of magnesium alloy sheet were studied.The microhardness testing,metallographic microscopy technique and X-ray diffraction technique were used to test the mechanical properties and characterize the microstructure of samples deformed and annealed at different deformations and temperatures.The microstructure evolution of Mg-3Gd alloy during high-throughput rolling and annealing was systematically studied,the mechanical behavior and recrystallization mechanism of samples with different microstructures;the evolution process of texture was analyzed,and the following conclusions were mainly obtained:(1)Wedge-shaped cast Mg-3Gd alloy was heated at 450?for 10 minutes,then the Mg-3Gd alloy plate with gradient structure was prepared by two pass rolling processes with a total deformation of 50%.During the rolling process,the microhardness value of the alloy increases as the deformation rate increases.During the annealing process,the hardness of the alloy first increased and then decreased,and the maximum value was obtained at 200?,which was 79.7 HV,and the hardness value at400?was 50%of the maximum value.(2)Analyze the metallographic microstructure of samples with different deformation rates.It was found in turn that the samples have microstructures such as twins,deformation bands and shear bands appearing in the RD direction with the increase of the deformation degree,and the number of twin grains increase with the deformation.Gradually get refined.(3)The recrystallization temperature T₅₀is about 300?.The performance of the annealed material at 400?has decreased,but the overall performance is still better than the as-cast sample.The average grain size after annealing at 350?was 15.72?m,and the average grain size after annealing at 400?was 25.57?m.(4)XRD macro texture analysis of the material revealed that the main texture type of the magnesium alloy after rolling was(0002)basal texture.As the deformation rate rises,the texture strength of the material increases,and the trend of base polarization becomes more pronounced.During the annealing process,the main texture type of the material did not change,but the texture strength decreased.Non-base surface slip also plays an important role in the deformation of magnesium alloys.