Preparation And Properties Of Fe₃Al/Al₂O₃ Nanocomposite Ceramics

Al₂O₃ ceramics have series of excellent properties such as high-temperature resistance, wearing resistance and etching resistance, but its brittleness seripusly limit the practical usages. So the toughening to Al₂O₃ Ceramics Ceramics in recent years become one of the important issues. Fe₃Al intermetallic compound has a long-range order special structure, its strength at high temperature, high temperature creep and oxidation resistance superior to most of metal materials, toughness is better than ceramic materials, so that it was thought be a new high temperature structural materials between the high-temperature alloys and ceramics. In recent years, the use of intermetallic compounds for toughening of ceramics made good results.In this paper, the main purpose of the study is the use of Fe₃Al ceramic particles improve the toughness of Al₂O₃. Fe₃Al/Al₂O₃ composite ceramics were prepared by Al₂O₃ as based ceramic body and Fe3Al intermetallic compounds as the toughening of the composite reinforcement.In this paper. Fe₃Al/Al₂O₃ composite materials were prepared by atmospheric pressure sintering and hot-pressure sintering , the Process parameters were amount of Fe₃Al. molding pressure, sintering temperature and sintering time. The microstructure were analysis by X-ray diffraction (XRD), SEM, electronic probe microanalyzer and optical microscope , while the density of materials, hardness and fracture toughness were tested, and discussed the tough composite material mechanism.The results showed that (1) Fe₃Al has the functioninto of refined grain .the grain size of material made by atmospheric pressure sintering were around 300nm . the grain size of material made by hot-pressure sintering were around 500nm. (2) The materials have good mechanical properties by adding Fe₃Al and hardness is 975Mpa respectively,fracture toughness is 8.3 MPa/ml/2 respectively. (3) the density and mechanical properties of materials improved with suitable extened molding pressure , sintering temperature, sintering time. (4) the density and mechanical properties of materials made by hot-press sintering were better than the material's made by atmospheric pressure sintering...