The microstructure and properties of Mg-Zn-Y-(ZrB2)enhanced by long period stacking were studied by means of optical microscope,scanning electron microscope,XRD diffractometer,electronic universal testing machine and direct extrusion experiment in this work.The results show that the as-cast Mg94Zn25Y25 alloy is composed of α-Mg matrix phase,block LPSO phase and network W phase.The addition of ZrB2 can refine the grain,promote the formation of LPSO phase and inhibit the precipitation of W phase.When the addition content of ZrB2 is 0.3wt.％,the alloy achieves the finest microstructure and the best mechanical properties.The grain size of alloy was refined from 42.6 μm to 22.8 μm,the yield strength increased from 131 MPa to 180 MPa,the tensile strength increased from 172 MPa to 225 MPa,and the elongation increased from 6.9％to 17.5％.After solid solution treatment and extrusion at different temperatures(350 ℃,400 ℃,450 ℃),it was found that the alloy exhibited the best mechanical properties after extrusion at 350 ℃,the yield strength was 305 MPa,the tensile strength was 358 MPa,and the elongation was 21％.
关键词
镁合金/长周期堆垛有序结构/正挤压/ZrB2
Key words
magnesium alloy/long period stacking ordered structure/direct extrusion/ZrB2
万方数据