Synthesis of Fe_3Al-Al_2O_3 composite powders by mechanochemical reaction

Fe3Al-Al2O3 nano-composite powders were synthesized by mechanochemical reaction of Fe3O4-Al powder mixtures.Phase evolution and structural development during ball milling were investigated by XRD,SEM equipped with EDS.The results show that after milling for 30 min,a small quantity of Al2O3 is formed.Most of Fe3O4 is reduced by Al and α-Al2O3,θ-Al2O3,Fe(Al) solid solution and FeO are formed after milling for 1 h.After milling for 3 h,θ-Al2O3 is transformed to α-Al2O3,while Fe(Al) solid solution,FeO and the residual Al are transformed to FeAl intermetallic and Fe.911O due to the mechanical force.Continuous milling for 5 h,FeAl intermetallis reacts with Fe.911O completely and Fe3Al-Al2O3 composite powders are obtained.The mechanically activated reaction between Fe3O4 and Al is suddenly occurring type and the critical milling time is 50 min.