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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 Mg_ (94) Y_4Zn_1Ni_1 (at%) alloy during casting, annealing, extrusion and aging were investigated by OM, SEM, TEM and electronic universal testing machine. The results show that the as - cast alloy consists of cellular α - Mg phase, networked 18R LPSO phase and massive Mg_ (24) (Y, Zn, Ni) _5 phases. After annealing, the alloy did not precipitate 14H LPSO phase. After extrusion deformation, the 18R LPSO phase was transformed into a long strip and arranged along the extrusion direction. The tensile strength of extruded alloy reached 417 MPa, which was significantly higher than that of as-cast and annealed alloys. After T5 and T6 aging treatment, a large number of small coherent β ’precipitates precipitated in the matrix of the alloy, and the alloy was further strengthened. The tensile strengths of T5 and T6 alloys were 434 and 432 MPa, respectively, and the yield strengths were both higher than 300 MPa.