Effect Of Alloying Element And Technical Parameter On Structure By TEM Of Bulk Nanocrystalline Fe₃Al Materials Prepared By Aluminothermic Reaction

In this paper average grain sizes and crystal structure of bulk nanocrystalline Fe3Al materials prepared by aluminothermic reaction are studied in the different technical parameters, addition to Mn,Cr,Ni,Cu,Mo element and annealing. Effect rules of the different technical parameters, the different element and annealing on nanostructure of the bulk nanocrystalline Fe3Al materials are discussed.Main results and conclusions are as follows:1.With the argon gas pressure, the materials are mainly composed of nanocrystalline and a certain amount of amorphous. Average grain sizes of nanocrystalline phase decreased with the argon gas pressure increasing.Average grain sizes are less than 30 nm. The structure of the materials is DO3.2.The effect of diluter on the amount of every phase in materials is not remarkable. With content of diluter increasing, Average grain sizes of nanocrystalline decreased, and content of amorphous is increased.The structure of the materials is DO3.3.With content of Ni increasing, average grain sizes and the structure of the materials is not changed.The structure of the materials is bcc.After annealing, the grain size of nanocrystalline decreased. The structure of the materials is transformed from bcc into DO3 when annealing temperature achieved 1000℃.4.With content of Mn increasing, average grain sizes of bulk nanocrystalline Fe3Al materials decreased.The structure of the materials is bcc.After annealing, some like-needle Mn appear and the structure of the materials is not changed.With annealing temperature increasing, average grain sizes of nanocrystalline phases decreased first and then increased.5.With content of Cr increasing, average grain sizes of bulk nanocrystalline Fe3Al materials is not changed.The structure of the materials is bcc. After annealing, average grain sizes and the structure of the materials are not changed.6.With content of Cu increasing, average grain sizes of bulk nanocrystalline Fe3Al materials increased first and then decreased. The structure of bulk Fe3Al nanocrystalline materials containing Cu 5 wt.% and 15 wt.% is bcc. The structure of the materials containing Cu 10 wt.% is DO3.After annealing, average grain sizes of nanocrystalline phases of the materials containing Cu 5 wt.% gradually increased. The structure of the materials is transformed from bcc into DO3.7.With content of Mo increasing, average grain sizes of bulk nanocrystalline Fe3Al materials increased first and then decreased. The structure of bulk Fe3Al nanocrystalline materials containing Mo 5 wt.% and 10 wt.% is bcc. The structure of the materials containing Mo 15 wt.% is DO3.