Research On The Heat Treatment Process Of Spray Forming 7075 Aluminum Alloy

With high strength and high toughness Aluminum Alloy,7 series aluminum alloys widely used in the area of aerospace and automotive.Spray forming is an advanced forming technology,which plays a significant role in the area of aluminum alloys strengthen.At the same time,alloy strength increase by thermomechanical treatment.The organization and mechanical properties change with different heat treatment system of for extruded spray forming 7075 were studied,and the microstructure,mechanical properties and corrosion resistance were studied also in processing of low temperature thermomechanical treatment.The results show that the microstructure of the alloy prepared by spray forming technology is obviously uniform,refined and equiaxed coMPared with the cast alloys,But the metallurgical quality of the alloy is relatively low,and the subsequent densification treatment needs to be carried out.After being extruded,the equiaxed structure of the deposit is elongated in the direction of extrusion,dislocation occurs in the alloy,and there is energy in the alloy,and recrystallization occurs in the solution process.After T6 treatment,the mechanical properties of the alloy are maximum: The tensile strength of the alloy is 660 MPa,and the yield strength is 635 MPa,elongation is 10.6%.The optimum process is as follows: the solution temperature is 490?,single stage aging 24 h.In the aging process,double aging and creep aging improve the strengthening effect,but weaker than single aging,aging bipolar optimal scheme:130?×3h+160?×12h,creep aging process is 150?+200MPa+15h?In the low temperature thermomechanical treatment,the mechanical properties of the alloy are the best at deformation of 15%.With the increasing of deformation,the dislocation density and internal energy increased,as results,the precipitation hardening response time became shorter,the larger the dislocation density not only caused uneven precipitation phase nucleation,but also the organization crack growth caused,all these reduced the strength of the alloy.The deformation heat treatment process can improve the strength of the alloy,reduce the shaping of the alloy,and also reduce the corrosion resistance.The deformation more larger,the corrosion resistanceworse.