(昆明理工大學(xué) 材料科學(xué)與工程學(xué)院，昆明 650093)
摘 要: 研究Mn元素對高純Mg-3Al(質(zhì)量分?jǐn)?shù)，%)合金晶粒尺寸的影響。結(jié)果表明：當(dāng)合金中的Mn元素含量小于0.21%(質(zhì)量分?jǐn)?shù))時，合金的晶粒尺寸變化不大；但當(dāng)Mn元素含量大于0.21%時，Mn元素的存在則使合金的晶粒尺寸迅速增大；Mn元素的作用主要與影響熔體中含碳晶核的形核能力有關(guān)；當(dāng)Mn元素的含量小于其溶解度時，Mn元素對含碳晶核的形核能力影響不大，但當(dāng)Mn元素的含量達(dá)到或超過其溶解度時，Mn元素對含碳晶核的影響迅速增大，最終導(dǎo)致含碳晶核的形核能力降低，引起晶粒粗化。
關(guān)鍵字: 鎂合金；Mn；晶粒細(xì)化；異質(zhì)形核
（Faculty of Material Science and Engineering,
Kunming University of Science and Technology, Kunming 650093, China）
Abstract:The effect of Mn on the grain size of high-purity Mg-3Al (mass fraction, %) alloys was investigated. The results show that the grain sizes of high-purity Mg-3Al alloys changes little when the Mn content is lower than 0.21% (mass fraction), while the grains are coarsened when Mn content is higher than 0.21%. The effect of Mn is relative to the heterogeneous nucleation of carbon-containing cores in the melt. When Mn content is low and dissolves into the melt, the nucleating potent of carbon-containing cores would not be influenced basically. But when Mn content in the melts is close to or higher than its solubility, the nucleating potent of the cores is decreased by Mn addition, and the grains are coarsened.
Key words: magnesium alloy; Mn; grain refinement; heterogeneous nucleation
