Correlation Study Of Microstructure And Properties Of 5056 Aluminum Alloy Wire

5056 aluminum alloy is an Al-Mg alloy with high plasticity,good strength,and excellent corrosion resistance in the annealed heat treatment condition,and high quality 5056 aluminum alloy wire has been the main raw material for aerospace core rivets.In this thesis,we studied the effect of final cold drawing deformation and annealing heat treatment parameters on the properties of 5056 aluminum alloy wire based on the evolution of the grain structure of the wire.The influence of the final cold drawing deformation and annealing heat treatment(including complete annealing and stabilized annealing)on the organization and properties of 5056 aluminum alloy wire was investigated,and the correlation of the organization and properties of 5056 wire was discussed,and the following conclusions were obtained:With the increase of cold drawing deformation from 24.2%,38.6%to 44.3%in the final pass,the degree of deformation of the wire cold drawing state organization increased,the average grain size decreased,the strength increased,the elongation decreased,and the work hardening effect of the wire was significant.After stabilized annealing heat treatment,the wire undergoes different degrees of recovery,strength decreases,elongation increases,and the highest uniformity of grain organization is achieved at 38.6%deformation,with the smallest average size of 10.8 ?m.After the complete annealing heat treatment at higher temperatures,the wire underwent complete recrystallization,with a significant decrease in strength and a significant increase in elongation,with the highest grain homogeneity and the smallest average size of 14.2 ?m at 44.3%deflection.The final pass cold drawing deformation of the wire matched with complete annealing and stabilized annealing were determined to be 44.3%and 38.6%,respectively.The evolution of the organization and properties of the wire with 44.3%cold-drawn deformation in the final pass was studied during the complete annealing heat treatment.It was found that when the wire was held for 2 h,a small amount of recovery occurred after annealing at 250? compared with the cold-drawn wire,but the deformation was still dominant,and there was a high density of dislocation entanglement and a small amount of substructure in the tissue;the degree of recovery increased after annealing at 260?,and significant recrystallization occurred after annealing at 270?,indicating that the average orientation difference fraction of 0?1° grains in the fully recrystallized ratio was 95.3%.The tissue has completed recrystallization after annealing at 280?,and the degree of recrystallization reached 98.8%,with uniform and fine organization;the recrystallization ratio did not change significantly when the annealing temperature was subsequently increased again.With the increase of annealing temperature,the average grain size tends to increase.The strength decreases with the increase of annealing temperature from 250? to 280?,and the elongation increases;the tensile strength,yield strength and shear strength are basically stable at annealing temperature from 280? to 460?,and the elongation is between 32.7%and 36.8%.The microstructure and strength of the wire did not change significantly when the holding time was extended at annealing temperature of 280?.After the annealing treatment at 280?/2 h,the tissue was completely recrystallized,the grain size was uniform and fine,the average grain size was 13.9 ?m,the tensile strength,yield strength and shear strength were 288 MPa,140 MPa and 177 MPa,respectively,and the elongation was 32.7%.The evolution of the organization and properties of the wire with 38.6%cold-drawn deformation in the final pass was studied during the stabilized annealing heat treatment.The average grain size was not significantly different.After heat treatment at 240?,a large number of sub-crystals were formed,the dislocation density was significantly reduced,and the highest degree of uniformity and fineness was observed.The strength of the wire did not change significantly when the stabilized annealing temperature was 230??240?;when the stabilized annealing temperature reached above 250?,the strength of the wire decreased significantly.The microstructure and strength of the wire did not change significantly when the stabilized annealing temperature was 240? for 0.5 h,1 h,2 h and 4 h,respectively,and the elongation was between 17.8%and 21.4%.After the 240?/2 h annealing treatment,the highest degree of uniformity and fineness of the tissue was observed,with an average grain size of 9.1 ?m,tensile strength of 345 MPa,yield strength of 240 MPa,shear strength of 189 MPa,and elongation of 19.7%.