挤压ZAT522镁合金的组织与力学性能研究

Research on Microstructure and Mechanical Properties of Extruded ZAT522 Mg Alloy

研究了均匀化态与挤压态Mg-5Zn-2Al-2Sn(ZAT522)合金的微观结构、织构和力学性能。结果表明:挤压合金为完全动态再结晶结构,具有双峰晶粒尺寸。挤压合金的平均晶粒尺寸为11.2μm,在晶界与晶粒内部析出了大量细小Mg2Sn相,析出相的不均匀分布是导致双峰晶粒结构的主要原因;挤压合金中形成强的基面织构。此外,与均匀化合金相比,挤压的ZAT522合金具有优异的力学性能,其抗拉强度255 MPa、屈服强度114 MPa、伸长率32%。挤压合金强度显著增加主要归因于晶粒细化、沉淀强化和织构强化。

The microstructure, texture and mechanical properties of as-homogenized and extruded Mg-5 Zn-2 Al-2 Sn(ZAT522) alloys were investigated. The results show that the extrusion alloy exhibits a fully dynamically recrystallized microstructure with a bimodal grain size. The average grain size of the extruded alloy is 11.2 μm and a strong basal texture appears. The fine Mg2 Sn phases precipitate dynamically during the extrusion, and its inhomogeneous distribution results in the formation of the bimodal grain structure. In addition, compared with as-homogenized alloy, the extruded ZAT522 alloy shows a excellent ultimate tensile strength of 255 MPa, yield strength of 114 MPa, and elongation of 32%. The remarkable increase in the strength of extruded alloy attributes to the grain refinement, precipitation strengthening and dand texture strengthening.