多道次搅拌摩擦加工AZ31镁合金宽板的组织与性能

通过重叠率为0.5的多道次搅拌摩擦加工(Multi-pass friction stir processing,MFSP)成功制备出了无缺陷的AZ31镁合金宽板,对板材的组织、宏观织构、各方向的拉伸性能及断口形貌等进行了测试分析。结果表明,由于搅拌区的动态再结晶作用,板材的晶粒尺寸从165μm细化到12.9μm,细化效果显著。与轧制母材相比,MFSP宽板的抗拉强度与屈服强度有所下降,但是塑性得到了明显提高,加工方向伸长率由16%提高到46.6%,垂直于加工方向的样品伸长率由16%提高到24.4%。板材的力学性能存在一定的各向异性,通过断口观察发现这可能与多道次加工的不均匀过渡区有关。

Microstructure and mechanical properties of AZ31 magnesium alloy plate prepared by multi-pass friction stir processing

The wide plate of AZ31 magnesium alloy with no defects was successfully prepared by multi-pass friction stir processing(MFSP) with an overlapping ratio of 0.5, and microstructure, macro-texture, tensile properties and fracture morphology of the MFSP wide plate were analyzed. The results show that the grain size of the plate is refined from 165 μm to 12.9 μm due to the dynamic recrystallization of the stirring region during MFSP, and the refining effect is significant. Compared with the rolling base material, the tensile strength and the yield strength of the MFSP wide plate decrease slightly, but the plasticity is obviously improved, the elongation of the the sample at processing direction is increased from 16% to 46.6%, and the elongation of the sample perpendicular to the processing direction is increased from 16% to 24.4%. The mechanical properties of the MFSP wide plate have a certain anisotropy, through the fracture observation, it is found that this may be related to the non-uniform transition zone of the multi-pass processing.