循环扩挤变形AZ80镁合金的组织、织构与力学性能

发布时间：2018-04-04 15:32

本文选题：循环扩挤　切入点：AZ镁合金　出处：《材料导报》2017年16期

【摘要】：采用循环扩挤(Cyclic expansion-extrusion,CEE)变形工艺对AZ80镁合金的块状材料进行热挤压加工,观察试样的微观组织与织构,并测试了力学性能。结果表明:AZ80镁合金经过CEE变形后,晶粒的尺寸明显细化,第4道次CEE变形之后,晶粒尺寸从150~230 μm细化至2 μm,整体分布均匀且呈等轴晶;2道次变形后,随着挤压道次的增加,晶粒的细化程度减慢;同时经过CEE变形的AZ80镁合金织构包括了(0001)基面平行于挤压方向与(1120)棱柱面垂直于挤压方向的两种不同纤维织构,随着挤压道次的增加,织构总体强度出现先减后增再减的变化;力学性能相对于均匀化态有着明显的变化,第1道次CEE变形之后,抗拉强度与屈服强度分别达到各自的最大值,为290 MPa和180 MPa,第2道次CEE变形之后,强度出现不随晶粒细化而增强的现象(反Hall-Petch理论),这是因为织构的软化作用强于晶粒的细化作用,而伸长率随着挤压道次的增加而提高。
[Abstract]:The AZ80 magnesium alloy bulk material was hot extruded by cyclic cyclic expansion-extrusioning (CEE) process. The microstructure and texture of the sample were observed and the mechanical properties were tested.The results show that after CEE deformation, the grain size of the alloy is obviously refined. After the fourth step of CEE deformation, the grain size is refined from 150 ~ 230 渭 m to 2 渭 m. The grain size of the alloy is uniform and equiaxed after two times of deformation, and with the increase of extrusion pass, the grain size of the alloy is increased with the increase of extrusion pass.At the same time, the grain refinement of AZ80 magnesium alloy deformed by CEE includes two different fiber textures, which are parallel to the extrusion direction and 1120) prism, which are parallel to the extrusion direction and perpendicular to the extrusion direction.The total strength of texture decreases first and then increases and then decreases, and the mechanical properties are obviously different from homogenization. After the first pass CEE deformation, the tensile strength and yield strength reach their respective maximum, respectively.For 290 MPa and 180MPa, after the second pass CEE deformation, the strength does not increase with grain refinement (anti-#en2# theory, this is because texture softening is stronger than grain refinement, and elongation increases with the increase of extrusion pass number).
【作者单位】：中北大学材料科学与工程学院;中北大学机电工程学院;
【基金】：山西省自然科学基金(2013011022-5)
【分类号】：TG146.22;TG379

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