Al-Zr及Al-Zr-O体系铝基原位复合材料的制备与组织研究

Research of Preparation and Microstructures of In-Situ Al Matrix Composites in the System Al-Zr and Al-Zr-O

利用Al Zr及Al Zr O体系,应用熔体反应法,成功制备了内生ZrAl3和Al2O3颗粒增强铝基复合材料。用扫描电镜(SEM)、电子探针(EPMA)等研究了(ZrAl3+Al2O3)P/Al复合材料的凝固组织、内在增强体的特征和界面结构。试验结果表明,随着反应物K2ZrF6、ZrSiO4、ZrOCl2粉剂的加入量增加,合金组织中生成的ZrAl3和Al2O3颗粒尺寸更细小,分布更均匀;生成的增强体Al2O3为六方晶体,尺寸为1～3μm;生成的ZrAl3为四方晶体,尺寸<1μm。颗粒增强铝基复合材料经Sr变质处理后,内生颗粒不再被凝固界面排斥和推移,而是大部分被捕捉进入固相,从而使内生颗粒较均匀的分布于基体中。

A novel in-situ reaction system Al-Zr and Al-Zr-O is firstly developed. On the basis of analyzing various in-situ synthesized processes, a new in-situ reactive technique, called direct melt reaction method, has been adopted. In situ ZrAl3 and Al2O3 particulate reinforced aluminum matrix composites have been fabricated successfully. The solidification microstructure, in-situ particulate features, interfacial structure and mechanical properties of (ZrAl3 + Al2O3)/Al composites have been investigated using Scanning Electron Microscope (SEM), Electron Probe Micro-analyzer (EPMA) and other modern equipment. The nature and mechanism of these characteristics have been analyzed. It is found that in-situ formed particles in the system Al-Zr-O are finer and are well distributed in the Al matrix. The maximum sizes of Al2O3 and ZrAl3 particulate are 3 μm and 1 μm respectively. After modification by Sr, the endogenous particles of particulate reinforced aluminum matrix composites are no longer been repulsed and traction. Instead, most of them have been trapped into solid phase. Thus, the endogenous particles are well-distributed in the matrix.