含LPSO相Mg_(94)Y_4Zn_1Ni_1合金的组织和力学性能

Microstructure and Mechanical Properties of Mg_(94)Y_4Zn_1Ni_1 Alloy with Long Period Stacking Ordered(LPSO) Phase

采用OM、SEM、TEM和电子万能试验机研究了Mg_(94)Y_4Zn_1Ni_1(at%)合金在铸态、退火、挤压和时效态的显微组织与力学性能。结果表明:铸态合金组织由胞状α-Mg相、网状18R LPSO相和块状Mg_(24)(Y,Zn,Ni)_5相组成。退火后,合金中未析出14H LPSO相。经挤压变形,18R LPSO相转变为长条状并沿挤压方向排列,挤压态合金的抗拉强度达到417 MPa,显著高于铸态和退火态合金。经过T5和T6时效处理,在合金的基体中析出大量细小的共格β'沉淀相,合金得到进一步强化。T5态和T6态合金的抗拉强度分别为434和432 MPa,屈服强度均高于300 MPa。

The microstructure and mechanical properties of Mg94Y4Zn1Ni1 alloy in as-cast, as-annealed, as-extruded and aged states were investigated by OM, SEM, TEM and electronic universal testing machine. Results show that the as-cast alloy is composed of μ-Mg matrix, 18R long period stacking ordered （LPSO） structure and Mg24（Y, Zn, Ni）5 phase. During hot extrusion, the 18R phases become stripy and are aligned in lines along the extrusion direction. The ultimate tensile strength of as-extruded alloy reaches 417 MPa. After aging, a large number of coherent β＇ phases are precipitated in α-Mg matrix, and as a result the strength of the alloy is enhanced further. The T5-treated and T6-treated alloys exhibit ultimate tensile strength of 434 and 432 MPa, respectively.