2Si可以顯著提高合金的硬度、耐磨性，特別是耐高溫蠕變性。但鑄態(tài)過共晶Mg-Si合金中初生Mg2Si棱角粗糙，共晶Mg2Si具有復雜的漢字形態(tài)，會嚴重割裂合金基體。為了改善Mg-2.5Si-4Zn合金的性能，進行了添加Er/Er-Ba的變質(zhì)實驗，并通過光學顯微鏡（OM）、掃描電子顯微鏡（SEM）、能量色散光譜儀（EDS）和X射線衍射儀（XRD）研究了Er/Er-Ba對合金組織和Mg2Si相的影響。利用計算機輔助電子加載拉伸試驗機對力學性能進行了測試和分析。結(jié)果表明，在Mg-2.5Si-4Zn合金中加入0.6%（質(zhì)量分數(shù)）的Er，其組織中的初生Mg2Si從粗大的樹枝狀轉(zhuǎn)變?yōu)橐?guī)則的四方塊狀，而共晶Mg2Si則從粗大的漢字狀轉(zhuǎn)變?yōu)楦鼜碗s的短棒狀。隨后加入0.8%的Ba后，初生Mg2Si從規(guī)則的四邊形塊狀進一步轉(zhuǎn)變?yōu)閹в袦喜酆涂锥吹牟灰?guī)則細小塊狀，共晶Mg2Si在尺寸上細化效果顯著，呈點線狀彌散分布在合金基體中。當加入0.6%Er和0.8%Ba時，變質(zhì)效果最佳。經(jīng)Er-Ba復合變質(zhì)的Mg-2.5Si-4Zn合金的力學性能得到顯著改善，抗拉強度σb和伸長率δ分別提高到168 MPa和5.04%。;The enhanced phase Mg2Si in the magnesium alloy can significantly improve the hardness, wear resistance, especially high temperature creep resistance. But the Mg2Si phase of the as-cast hyper-eutectic Mg-Si alloy will seriously cut the alloy matrix because of the coarse angular shape of the primary Mg2Si and complex Chinese script morphology of the eutectic Mg2Si. In order to improve the properties of Mg-2.5Si-4Zn alloy, the modification experiments of adding Er/Er-Ba were performed and the effects on the alloy microstructure and Mg2Si phase were investigated by the optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray diffractometer (XRD). The mechanical properties were measured and analyzed by the computer-aided electric-loaded tensile tester. The results show that with the addition of 0.6wt% Er to the Mg-2.5Si-4Zn alloy, the primary Mg2Si in the microstructure transforms from a coarse dendritic shape into a regular tetragonal block shape, while the eutectic Mg2Si transforms from a coarse Chinese script type to a more complex short rod shape. When adding 0.8wt% Ba subsequently, the primary Mg2Si further transforms from a regular tetragonal bulk shape to an irregular fine bulk shape with grooves and holes, and the eutectic Mg2Si has an obvious refining effect and is diffusely distributed with the dot/short-line shape in the alloy matrix. The best metamorphic effect is obtained by adding 0.6wt% Er and 0.8wt% Ba. The mechanical properties of the Mg-2.5Si-4Zn alloy modified by Er-Ba composite modifier are significantly improved, with the tensile strength σb and elongation δ increasing to 168 MPa and 5.04%, respectively."/>
2Si;組織;復合變質(zhì);力學性能;Mg-Si-Zn alloy;Mg2Si;microstructure;composite modification;mechanical properties"/>