動力學(xué)模型
(江蘇大學(xué)材料科學(xué)與工程學(xué)院， 鎮(zhèn)江 212013)
摘 要: 開發(fā)了Al-Zr(CO3)2體系熔體反應(yīng)法合成新型(Al3Zr+Al2O3)p/Al復(fù)合材料， 研究了Al-Zr(CO3)2體系的反應(yīng)熱力學(xué)、 反應(yīng)動力學(xué)及反應(yīng)機(jī)制。 結(jié)果表明： Al-Zr(CO3)2體系起始反應(yīng)溫度為850℃， 且在鋁熔體(850～1100℃)溫度范圍內(nèi)反應(yīng)能自發(fā)進(jìn)行。 X射線衍射(XRD)及掃描電鏡(SEM)分析表明： 反應(yīng)合成的強(qiáng)化相為Al3Zr和α-Al2O3顆粒， 其尺寸為0.1～1μm， 且在基體中彌散分布。 反應(yīng)過程中復(fù)合熔體水淬實驗分析表明： 反應(yīng)析出的Zr量隨反應(yīng)時間延長而增大， 當(dāng)反應(yīng)進(jìn)行10min就達(dá)到了總增量的90%， 整個合成反應(yīng)時間為15min， 且合成過程前期(反應(yīng)3min前)主要受化學(xué)反應(yīng)控制， 合成過程后期(反應(yīng)10min后)主要受擴(kuò)散控制。 Al-Zr(CO3)2體系中關(guān)鍵反應(yīng)ZrO2與Al按反應(yīng)-擴(kuò)散-破裂機(jī)制進(jìn)行， 并建立了反應(yīng)原理圖、 反應(yīng)動力學(xué)模型和反應(yīng)時間的動力學(xué)方程。
關(guān)鍵字: Al-Zr(CO3)2體系； 反應(yīng)機(jī)制； 動力學(xué)模型； 熔體反應(yīng)法； 原位復(fù)合材料
CHENG Xiao-nong, LIN Dong-yang
（School of Materials Science and Engineering, Jiangsu University,Zhenjiang 212013, China）
Abstract: Novel in-situ (Al3Zr+Al2O3)p/Al composites was developed by direct melt reaction in the system Al-Zr(CO3)2. The reactive thermodynamics, kinetics, and mechanism of in-situ Al-Zr(CO3)2 system were investigated. The results indicate that the initial reactive temperature of Al-Zr(CO3)2 system is 850℃. The reaction between Zr(CO3)2 powder and aluminum melt can proceed spontaneously at the range of 850-1100℃. X-ray diffraction (XRD) and scanning electron microscope (SEM) analyses indicate that the in-situ formed reinforcements are Al3Zr and α-Al2O3 particles. The size of these particles is in the range of 0.1-1μm. These particles are well distributed in the matrix. Analysis of water-quenched samples during reactive process shows that zirconium content in aluminum melt increases rapidly with the increasing reactive time and increases by 90% for 10min. The whole time of in-situ synthesis is 15min. In-situ synthesis process in Al-Zr(CO3)2 system is controlled mainly by chemical reaction at earlier stage (before 3min), whereas it is controlled mainly by the particulate diffusion at later stage (after 10min). The mechanism of key reaction between ZrO2 and Al in the system Al-Zr(CO3)2 is the reaction-diffusion-crack. Furthermore, the reactive kinetic model, the reactive principle sketch and, the reactive time formula in the system Al-Zr-O were established.
Key words: Al-Zr(CO3)2 system; reactive mechanism; kinetic model; direct melt reaction; in-situ composites
