Study On Continuous Rheo-Extrusion Of Al-Fe Alloy And Thermal Stability

Continuous rheo-extrusion technology has a significant effect on the grain fined and breakage of coarse iron rich phase in the Al-Fe alloy,which improve the mechanical property of the Al-Fe alloy.In this paper,study on the evolution of microstructure and mechanical property of the Al-Fe alloy by means of hardness and tensile test,as well as X-ray diffraction(XRD),electron backscattered diffraction(EBSD),scanning electron microscope(SEM)and transmission electron microscope(TEM),to explore its thermal stability.The main findings are as follows:(1)With the increase of the extrusion pass,the Fe-rich phase of Al-Fe alloy was broken to a certain extent and the Fe-rich phase size was reduced,indicating that the continuous rheo-extrusion has a significant effect on the crushing of coarse Fe-rich phase,Which helps to reduce the fragmentation of coarse Fe-rich matrix;with the increase of Fe content,the number of Fe-rich phase increases.(2)After two times of continuous rheological extrusion,the grain morphology of Al-l.5Fe alloy is equiaxed,and the proportion of large angle grain boundaries is 55.06%.After two passes of continuous rheo-extrusion,the Al-1.5Fe alloy still has good work-hardening ability,indicating that the Al-1.5Fe alloy has a certain degree of dynamic recrystallization.(3)The strength and hardness of Al-Fe alloy decrease with the increase of extrusion pass,and the elongation increases with the increase of extrusion pass.Al-Fe alloy has a certain degree of dynamic recrystallization during continuous rheo-extrusion,which is the main reason for the decrease of strength and hardness.(4)When the annealing temperature is in the range of 150?-200?,the grain size does not grow obviously,and the low angle grain boundaries have a larger proportion and the microstructure is recovered.After annealing at 250?,the proportion of large angle grain boundaries in the alloy increased significantly,indicating that recrystallization of the alloy began to occur.The grain size increases obviously after annealing at 350?,and the proportion of the large angle grain boundaries is 83.33%.This indicates that the alloy has completely recrystallized after annealing at 350?,and the growth of grain occurs in some areas.(5)Al-1.5Fe alloy began significant work hardening when Al-15Fe alloy annealed at 250?.With the increase of annealing temperature,the work hardening ability of Al-1.5Fe alloy increased remarkably.The strength and hardness of Al-1.5Fe alloy decrease with the increase of annealing temperature.The plasticity increases with the increase of annealing temperature.