Microstructures and Mechanical Properties of Mg-2Y-xZn (x=1, 2, 3 at%) Alloys

摘要:

研究了Mg-2Y-xZn (x = 1, 2, 3 at%)合金在铸态、退火态和挤压态的显微组织与力学性能。结果表明：随着合金中Zn含量的增加，合金显微组织中第二相依次为18R-LPSO相、（LPSO + W）混合物和W相。在退火过程中，层片状的14H-LPSO结构析出并沿块状18R-LPSO结构向基体中生长，W相由铸态时弯曲的条纹状转变为颗粒状。经过挤压变形后，LPSO结构和W相均沿挤压方向排列，合金性能得到大幅度提高，其中Mg-2Y-1Zn合金具有最好的室温力学性能，抗拉强度为320 MPa，延伸率达到11.2%

Abstract:

The microstructures and the mechanical properties of the Mg-2Y-xZn (x = 1, 2, 3 at%) alloys in as-cast, as-annealed and as-extruded conditions have been investigated. The results show that the 18R-LPSO phases are distributed in a continuous network mainly along the grain boundaries in the alloy with 1 at% Zn. With increasing of Zn content, the 18R-LPSO phase and W-phase coexist in Mg-2Y-2Zn alloy but only W-phase remains in Mg-2Y-3Zn alloy. The 14H-lamellas are precipitated from the block-shaped 18R-LPSO phases into the matrix, and W-phases are broken into particles during homogenizing annealing. After extrusion, the LPSO phases and W-particles are rearranged along the direction of extrusion. The tensile tests show that the as-extruded Mg-2Y-1Zn alloy exhibits the supreme UTS of 320 MPa, with an elongation of 11.2% at room temperature