热压烧结工艺制备Fe_3Al/Al_2O_3复合材料的物相组成和显微结构研究

Study on Phase Composition and Microstructure of the Fe_3Al /Al_2O_3 Composites Fabricated by Hot-pressing Process

本实验采用机械合金化工艺结合热处理工艺制备Fe3Al金属间化合物粉末,并将Fe3Al粉末与Al2O3粉末相混合制备Fe3Al/Al2O3复合粉末,并通过热压烧结工艺制备Fe3Al/Al2O3复合材料块材试样,对Fe3Al/Al2O3复合材料的物相组成,显微结构和力学性能进行研究。结果表明采用机械合金化工艺球磨60 h后得到Fe-Al金属间化合物粉末。并经过800℃和1000℃热处理后得到Fe3Al金属间化合物粉末。经过热压烧结后得到的Fe3Al/Al2O3复合材料块材主要有Fe3Al相和Al2O3相。Fe3Al/Al2O3复合材料的显微结构均匀致密。Fe3Al晶粒均匀分布在Al2O3基体中,Fe3Al晶粒的平均颗粒尺寸为3～4μm,而Al2O3基体颗粒尺寸为4～5μm。随着基体中Fe3Al合金含量的增加,Fe3Al/Al2O3复合材料的密度和相对密度逐渐增加;Fe3Al/Al2O3复合材料的抗弯强度和断裂韧性逐渐增加;Fe3Al/Al2O3复合材料的洛氏硬度和弹性模量逐渐降低。Fe3Al/Al2O3复合材料具有较高的力学性能是由于复合材料具有均匀致密的显微结构。

The Fe3Al intermetallics compounds powders were fabricated by mechanical alloying and heat treatment process. The produced Fe3 Al intermetallics compounds powders and Al2O3 powders were mixed together and the Fe3 Al/Al2O3 composite powders were produced. Then the Fe3 Al/Al2O3 composites bulks were fabricated by hot-pressing process. The phase composition, microstructure and mechanical properties of the Fe3Al/Al2O3 composites were investigated. The research results showed that the Fe-Al intermetallics compounds powders were fabricated by mechanical alloying for 60 h. The Fe3Al intermetallics compounds powders were fabricated by heat treatment at 800 ℃ and 1000 ℃. The XRD patterns showed that there existed the FeaAl phase and Al2O3 phase in sintered composites. The Fe3Al/ Al2O3 composites exhibited homogenous and compact microstructure. The mean particles size of Fe3Al intermetallics compounds was about 3-4 μm and the mean particles size of Al2O3 as about 4-5 μm. The density and relative density of the Fe3Al/Al2O3 composites increased gradually with the increase of FeaAl content. The fracture strength and fracture toughness of the Fe3Al/Al2O3 composites increased gradually with the increase of Fe3Al content. The elastic modulus and hardness of the Fe3Al/Al2O3 composites decreased gradually with the increase of Fe3Al content. The Fe3Al/Al2O3 composites exhibited high mechanical property due to the compact and homogenous microstructure.