| The strong basal texture is the main reason for the low plasticity and poor formability of wrought magnesium alloys.The optimization of basal texture is one of the main methods to improve the properties of magnesium alloys.The second phase in magnesium alloy can affect the recrystallization texture by inhibiting or promoting the nucleation and growth of recrystallized grains.In the present stuy,Mg-7.5Sn(wt.%)alloy is selected as the research object,and the effects of static/dynamic precipitates on the dynamic recrystallization and texture of Mg-7.5Sn(wt.%)alloy were investigated,in the objective to provide theoretical references for texture optimization of magnesium alloys.In addition,Mg-Sn alloy sheets with deformed microstructure were prepared by hot rolling.The microstructure and texture evolution of deformed Mg-Sn alloy during static recrystallization were studied,and the influence of static/dynamic precipitates on static recrystallization behavior and grain orientation of Mg-Sn alloy was analyzed.The mechanical properties of Mg-Sn alloys with microstructures were measured,and the strengthening and toughening mechanism was clarified.The main results of this paper were as follows.A large number of rod-like Mg2Sn phases precipitated in Mg-7.5Sn(wt.%)alloy after solution and aging treatment.With the increase of strain rate,the dynamic precipitates in the assolutionized and peak-aged samples decreased,which resulted in the increase of dynamic recrystallization.After hot deformation,the peak-aged alloy contained more precipitates and the size of precipitates was much smaller than the as-solutionized sample.The dynamic recrystallization degree of the peak-aged sample was lower than that of the as-solutionized sample because the fine precipitates was more effective in inhibiting dynamic recrystallization.After hot deformation,the two samplesexhibited a(0001)basal texture with the(0001)planes perpendicular to the compression direction,and t the dynamic recrystallization region showed an obvious weaker texture intensity compared with than the un-recrystallization region.Therefore,the samples compressed at high strain rate with a higher fraction of recrystallization regiona presented a weaker texture strength.In addition,the texture strength of the dynamic recrystallization region decreased with the increase of strain rate,which was mainly because more precipitates in the samples compressed at low strain rates inhibited the grain orientation deflection during dynamic recrystallization.The fine precipitates in the peak-aged sample could effectively inhibit the deflection of recrystallized grains and gave rise to an intensified texture.The precipitation behavior o and its effects on the texture of Mg-Sn alloy during static recrystallization were studied in the present study.The results showed that the tension and compression twins were the preferred sites of the static precipitation and recrystallization.With the increase of annealing time,the volume fraction of recrystallized regions increased and the number of precipitates increased.The as-rolled sample exhibited strong basal texture with(0001)planes paralleled to rolling plane.Annealing treatment did not change the texture type but weakened the texture strength of the as-rolled sample because the orientation deflection of recrystallization grains.The mechanical properties of Mg-Sn alloys with different microstructures were investigated.It was found that the rolling deformation significantly improved the strength and plasticity.The tensile strength of the as-solutionized and peak-aged samples after hot rolling was 202 MPa and 214 MPa,and the elongation was 4.5%and 7.4%,respectively.Annealing treatment reduced the strength of the sample,but significantly improved plasticity.These different mechanical properties were mainly related to precipitates,texture and recrystallization. |
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