Effect Of Adding Alloyment On Nanostructure Of Bulk Nanocrystalline Fe₃Al Materials Prepared By Aluminothermic Reaction

In this thesis,The chemical composition,grain size,crystal structure and hardness of bulk nanocrystalline Fe₃Al materials with(5wt-15wt)%Mn,Cr,Ni,Cu,Mo element prepared by aluminothermic reaction.The rules of effect of the different element on nanostructure,steucture and hardness of the bulk nanocrystalline Fe₃Al materials are summed up.The main conclusions are given in the following.1.With content of Mn increasing,grain size of bulk nanocrystalline Fe₃Al materials decrease,the materials are consisted of the nanocrystalline phase and contamination phase,The grain size of nanocrystalline is about 10 nm.The noumenon is Mn,Al,Fe.The contamination is Mn,O,S,Al.the hardness of nanocrystalline phase is increased at first,then decreased when the contain of Mn element is increased.The grain size of nanocrystalline phase is minished when the contain of Mn element increased.2.With content of Cr increasing,grain size of bulk nanocrystalline Fe₃Al materials decrease first and then increased,the materials are consisted of the nanocrystalline phase and contamination phase.The grain size of nanocrystalline is about 10 nm. The noumenon is Cr,Al,Fe.The contamination is O,S,Al.The hardness of nanocrystalline phase is decreased at first,then increased when the contain of Cr element is increased.The grain size of nanocrystalline phase is minished when the contain of Cr element increased.3.With content of Ni increasing,the materials are consisted of the nanocrystalline phase and contamination phase,The grain size of nanocrystalline is about 15 nm. The noumenon is Ni,Al,Fe.The contamination is O,S,Al.The hardness of nanocrystalline phase is increased when the contain of Ni element is increased.The grain size of nanocrystalline phase is no change.4.With content of Cu increasing,grain size of bulk nanocrystalline Fe₃Al materials increased at first and then decreased,the materials are consisted of the nanocrystalline phase and contamination phase,The grain size of nanocrystalline is about 20 nm.The noumenon is Cu,Al,Fe.The contamination is O,S,Al.The hardness of nanocrystalline phase is increased at first,then decreased when the contain of Cu element is increased.5.With content of Mo increasing,grain size of bulk nanocrystalline Fe₃Al materials increased at first and then decrease,the materials are consisted of the nanocrystalline phase and contamination phase,The grain size of nanocrystalline is about 20 nm.The noumenon is Mo,Al,Fe.The contamination is O,S,Al.the hardness of nanocrystalline phase is decreased at first,then increased when the contain of Mo element is increased.