Effect Of Multi-directional Strong Strain On Mechanical Properties And Microstructure Of Aluminum Bronze Alloy

Because of its excellent mechanical properties,aluminum bronze alloy is widely used to manufacture synchronizer rings,bearings,turbines and other automotive parts.Exploring the process of improving the mechanical properties of aluminum bronze alloy and analyzing its mechanism have a positive effect on improving the performance of automotive power transmission.In this paper,QAl9-4 aluminum bronze alloy was taken as the research object.The changes of hardness,tensile properties,fracture toughness and impact toughness of QAl9-4 aluminum bronze alloy were compared after different treatment processes.In order to explore the effects of different treatment processes on the mechanical properties of QAl9-4 aluminum bronze alloy,as well as the influence on the size,morphology,category and second phase distribution of the microstructure,the microstructure and morphology were observed by optical microscope(OM),transmission electron microscope(TEM)and scanning electron microscope(SEM).The results show that compared with the samples after traditional heat treatment,the hardness and strength of the samples were improved significantly after multi-directional forging(MF).The hardness and strength of the samples increased by 86 HV0.1 and 98 MPa,respectively.By observing the microstructure of the materials,it was found that the increase in dislocation density and grain refinement increased the hardness and strength of the samples,but the plasticity decreased significantly,and the elongation decreased from 22.08 % to 12.86 %.The plasticity of the samples were improved clearly after MF and aging treatment,and the elongation of the samples reached 21.41 %.Compared with the samples after MF,the hardness and strength of the samples after MF and aging treatment were slightly reduced,only decreased by 35.8 HV0.1,25 MPa.During the aging process,the reduction of residual stress and dislocation density improved the plasticity of the alloy.The improvement of the strength and the plasticity of the alloy were also conducive to the improvement of toughness.Compared with the samples after MF,the fracture toughness and impact toughness of the samples after MF and aging treatment were greatly improved.Take it all in all,MF and aging treatment can significantly improve the hardness,tensile strength,fracture toughness and impact toughness without losing its good plasticity.MF and aging treatment resulted in excellent comprehensive mechanical properties of QAl9-4 aluminum bronze alloy.