轧制工艺对Mg-1.5Mn-0.3Ce合金组织和性能的影响

Effect of Rolling Process on Microstructure and Properties of Mg-1.5Mn-0.3Ce Alloy

目的研究板材的轧制性能及轧制工艺对Mg-1.5Mn-0.3Ce合金板材微观组织及力学性能的影响规律,从而为该系列合金的轧制工艺优化提供有力的参考和依据。方法对Mg-1.5Mn-0.3Ce合金进行了520℃保温8h的短时固溶处理,使其平均晶粒尺寸达到43.6μm。随后,在250℃下进行47%的轧制变形。结果中低温、大变形轧制显著提升了合金的强度,其90°方向的屈服强度和抗拉强度分别达到了240MPa和279MPa,且断后伸长率为11.4%,而0°方向的屈服强度和抗拉强度则达到了186MPa和202MPa,且断后伸长率为7.1%。这种显著的性能提升归功于轧制过程中产生的多种微观结构演变。首先,晶粒内部产生了大量的孪晶和位错,为合金提供了额外的强度来源。其次,随着轧制变形量的增加,合金中析出了大量弥散分布的纳米颗粒,并诱导了细小的动态再结晶晶粒形成。这些细小的晶粒抑制了位错的运动,进一步提高了合金的强度。结论通过合理的热处理和变形工艺,可以有效控制Mg-1.5Mn-0.3Ce合金的微观结构,从而显著提高其力学性能,使其在汽车工业中拥有更广泛的应用前景。

The work aims to study the effect of the rolling properties and rolling process of the plate on the micro-structure and mechanical properties of the Mg-1.5Mn-0.3Ce alloy plate,so as to provide a strong reference and basis for the optimization of the extrusion and rolling process of this series of alloys.In this study,the Mg-1.5Mn-0.3Ce alloy was subject to short-term solution treatment at 520℃for 8 h,and the average grain size reached 43.6μm.Subsequently,a 47%rolling deformation was carried out at 250℃.The strength of the alloy was significantly improved by rolling at me-dium and low temperature and large deformation.The yield and tensile strength of the alloy reached 240 MPa and 279 MPa in the 90°direction,respectively,and the elongation after break was 11.4%,while the yield and tensile strength in the 0°direction reached 186 MPa and 202 MPa,and the elongation after break was 7.1%.This significant performance im-provement was due to the multiple microstructural evolutions that occurred during the rolling process.First,a large num-ber of twins and dislocations were generated inside the grain,providing an additional source of strength for the alloy.Secondly,with the increase of rolling deformation,a large number of diffusely distributed nanoparticles were precipitated in the alloy,and the formation of fine dynamic recrystallized grains was induced.These fine grains inhibited the move-ment of dislocations,further increasing the strength of the alloy.In conclusion,the results of this study show that the mi-crostructure of Mg-1.5Mn-0.3Ce alloy can be effectively controlled through reasonable heat treatment and deformation process,so as to significantly improve its mechanical properties and make it have a wider application prospect in the automotive industry.