(1. 上海交通大學(xué) 材料科學(xué)與工程學(xué)院，上海市鎂材料及應(yīng)用工程技術(shù)研究中心，上海 200240；
2. 上海交通大學(xué) 材料科學(xué)與工程學(xué)院，金屬基復(fù)合材料國家重點實驗室，上海 200240；
3. 中國科學(xué)院 上海應(yīng)用物理研究所，上海 201204)
摘 要: 通過同步輻射小角度X散射實驗方法(SAXS)、透射電鏡(TEM)分析和維氏硬度測試，研究Mg-12Gd合金等溫時效過程中的析出強化行為。結(jié)果表明：Mg-Gd合金時效過程中主要析出相為β′相，隨著時效時間的增加，析出相的徑向尺寸明顯增大，寬度方向增加較小，逐漸演變成為橢圓形。175 ℃時效180 h時，析出相回轉(zhuǎn)半徑為12.9 nm；隨著時效時間延長到360 h，析出相長大為13.4 nm；隨著時效時間繼續(xù)延長，析出相的尺寸增長速率減慢并最終趨向穩(wěn)定。透射電鏡結(jié)果表明：在175 ℃時效296 h時析出相大部分為β′相，有少量的β″相，β′相是寬5 nm，長13 nm的橢圓形，與小角度X散射結(jié)果一致。通過在200 ℃時效30 min的散射曲線能看出有析出相析出，剛析出時回轉(zhuǎn)半徑為2.5 nm，在225 ℃時效30 min時，析出相的回轉(zhuǎn)半徑為2.9 nm。
關(guān)鍵字: 鎂合金；小角度X散射；析出相；回轉(zhuǎn)半徑
（1. Shanghai Engineering Research Centre of Magnesium Materials and Application, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;
2. Key State Laboratory of Metal Matrix Composite, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;
3. Shanghai Institute of Applied Physics, Chinese Academy of Science, Shanghai 201204, China）
Abstract:The precipitation behavior of Mg-12Gd alloys during single aging process was studied by the synchrotron radiation small angel X-ray scattering (SAXS), transmission electron microscopy (TEM) analysis and Vickers hardness test. The results show that main precipitates of Mg-Gd alloy during aging process are β′ phases, and with the increase of aging time, the radial size of precipitates increases notably, whereas, the width of the precipitates increases a little. Therefore, the shape of the precipitates gradually changes into oval shape. The gyration radius of the precipitation particles is 12.9 nm after aging at 175 ℃ for 180 h, and with the increase of aging time to 360 h, the gyration radius of precipitation particles increases to 13.4 nm. And the size of the precipitation particles increases with the increase of aging time and goes to a stable value at last. The TEM results show that main precipitates after aging at 175 ℃ for 296 h are β′ phases with width of 5 nm and length of 13 nm, and a few β″ phases exist, which is consistent with the results of small angel X-ray scattering. Scattering curves of alloys aged at 200 ℃ for 30 min show that precipitates exist and the gyration radius of precipitation is 2.5 nm, while gyration radius of the precipitates after aging at 225 ℃ for 30 min is 2.9 nm.
Key words: magnesium alloy; small angle X-ray scattering; precipitation phase; gyration radius
