(有研工程技術(shù)研究院有限公司 有色金屬材料制備加工國家重點實驗室，北京 101499)
摘 要: 利用掃描電鏡(SEM)、能譜儀(EDS)、X射線衍射儀(XRD)、透射電鏡(TEM)等分析實驗手段研究熱處理對Mg-6Zn-xCe合金微觀組織的影響，同時利用激光熱導(dǎo)儀測試不同熱處理狀態(tài)下該系列合金的熱擴散系數(shù)，并計算合金的熱導(dǎo)率，探討組織變化對合金導(dǎo)熱性能的影響規(guī)律。結(jié)果表明：鑄態(tài)Mg-6Zn合金主要由α-Mg相及Mg7Zn3相組成，共晶組織隨著Ce含量的增加而不斷增多；經(jīng)過固溶處理，合金Mg7Zn3相基本回溶，Mg-Ce-Zn三元相發(fā)生轉(zhuǎn)變，由Ce5(Mg,Zn)41相轉(zhuǎn)變?yōu)镸g17Ce2相，呈顆粒狀，斷續(xù)分布于晶界，同一成分合金固溶后，基體中Zn含量明顯升高；時效處理后，基體中過飽和的Zn原子以MgZn和MgZn2相形式析出；不同熱處理狀態(tài)合金熱導(dǎo)率由大到小依次為時效態(tài)、鑄態(tài)、固溶態(tài)，隨Ce含量升高，不同狀態(tài)的合金熱導(dǎo)率呈下降趨勢。
關(guān)鍵字: Mg-Zn-Ce合金；熱處理；微觀組織；熱導(dǎo)率
（State Key Laboratory of Nonferrous Metals and Processes, GRIMAT Engineering Institute Co., Ltd., Beijing 101499, China）
Abstract:As the continuous development of electronic communication and aerospace industry, the application and update of new equipment with high-precision and high-power are becoming more and more frequent. In order to meet the needs of miniaturization of equipment, most components adopt integrated design, which brings difficulties in heat dissipation. Therefore, it is necessary to develop new lightweight materials which have high thermal conductivity to improve and ensure the life and work stability of equipment. The high thermal conductivity magnesium alloy can simultaneously meet the demand for lightweight and high thermal conductivity, it has become one of the research hot spots in the current magnesium alloy field. The effect of heat treatment on the microstructure of Mg-6Zn-xCe alloy was investigated by SEM, EDS, XRD, TEM, the thermal diffusivity of the alloy under different heat treatment conditions was tested by laser thermal conductivity tester, and the thermal conductivity of the alloy was calculated and the influence of microstructure changes on the thermal conductivity of the alloy was discussed. The results show that the as-cast Mg-6Zn alloy is mainly composed of α-Mg and Mg7Zn3 phases, and the eutectic structure increases with the increase of Ce content. After solution treatment, the Mg7Zn3 phase is basically dissolved back, and the binary phase Ce5(Mg,Zn)41 is transformed into Mg17Ce2 phase, which is granular and intermittently distributes in the grain boundary. The Zn content in the matrix of the same alloy increases significantly after solid solution. After aging treatment, supersaturated Zn atoms in the matrix precipitate as MgZn and MgZn2 phases. The aging alloy has the highest thermal conductivity while the solid solution alloy has the lowest. The thermal conductivity of alloys in different states shows a downward trend with the increase of Ce content.
Key words: Mg-Zn-Ce alloy; heat treatment; microstructure; thermal conductivity
