动力学模型
(江苏大学材料科学与工程学院， 镇江 212013)
摘 要: 开发了Al-Zr(CO3)2体系熔体反应法合成新型(Al3Zr+Al2O3)p/Al复合材料， 研究了Al-Zr(CO3)2体系的反应热力学、 反应动力学及反应机制。 结果表明： Al-Zr(CO3)2体系起始反应温度为850℃， 且在铝熔体(850～1100℃)温度范围内反应能自发进行。 X射线衍射(XRD)及扫描电镜(SEM)分析表明： 反应合成的强化相为Al3Zr和α-Al2O3颗粒， 其尺寸为0.1～1μm， 且在基体中弥散分布。 反应过程中复合熔体水淬实验分析表明： 反应析出的Zr量随反应时间延长而增大， 当反应进行10min就达到了总增量的90%， 整个合成反应时间为15min， 且合成过程前期(反应3min前)主要受化学反应控制， 合成过程后期(反应10min后)主要受扩散控制。 Al-Zr(CO3)2体系中关键反应ZrO2与Al按反应-扩散-破裂机制进行， 并建立了反应原理图、 反应动力学模型和反应时间的动力学方程。
关键字: Al-Zr(CO3)2体系； 反应机制； 动力学模型； 熔体反应法； 原位复合材料
（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
