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采用锂盐熔剂保护熔铸了Mg-8Li-4Zn-xY合金铸锭,并通过正挤压制成1mm的薄板。通过光学显微镜、扫描电镜、XRD分析及合金硬度测试,探讨合金的组织与力学性能。结果表明:Mg-8Li-4Zn-xY合金基体为β-Li(bcc)和α-Mg(hcp)相,析出强化相颗粒和化合物为Mg2Zn11,Mg72.05Zn27.95,MgZn,Mg2Y,MgY及未知相。随Y含量的增加,铸态基体组织得到细化,析出相数量增加。1mm正挤压变形态薄板材基体组织大小、形貌和β-Li相内弥散析出的强化相颗粒数量随着Y含量的提高没有明显变化,但α-Mg相由β-Li相包裹着被拉长并得到一定程度的细化,呈平行于挤压方向的条带状。β-Li相在协调塑性变形的同时发生了动态再结晶,晶界均匀分布着强化相颗粒。无论是铸态还是挤压后1mm的Mg-8Li-4Zn-xY合金薄板,随着Y含量的增加合金得到不同程度的强化,硬度均得到不同程度的提高。
The cast-in Mg-8Li-4Zn-xY alloy ingot was protected by a lithium salt flux and made into a 1 mm sheet by normal extrusion. The microstructure and mechanical properties of the alloy were investigated by optical microscopy, scanning electron microscopy, XRD and alloy hardness testing. The results show that the matrix of Mg-8Li-4Zn-xY alloy is β-Li (bcc) and α-Mg (hcp) phases and the precipitates are Mg2Zn11, Mg72.05Zn27.95, MgZn, Mg2Y, MgY and unknown phase. With the increase of Y content, the as-cast matrix microstructure is refined and the amount of precipitated phase increases. The microstructure and size of the substrate matrix and the number of phase particles dispersed in the β-Li phase did not change significantly with the increase of Y content, but α-Mg phase was surrounded by β-Li phase Elongated and get a certain degree of refinement, was parallel to the extrusion direction of the strip. The β-Li phase undergoes dynamic recrystallization while coordinating plastic deformation, and the grain phase strengthens uniformly. Whether the as-cast or extruded 1mm Mg-8Li-4Zn-xY alloy sheet, with the increase of Y content, the alloy was strengthened to different extents, and the hardness was improved to some extent.