Study On The Organization And Mechanical Properties Of 1060 Aluminum Alloy By Gradient Accumulative Roll Bonding

After accumulative roll bonding,aluminium alloys can be significantly strengthened,but when the grain size of aluminium alloys is refined to a certain extent,their plasticity decreases rapidly.In response to this problem,gradient acumulative roll bonding and postrolling annealing is proposed to improve the strong plasticity of the alloy.Therefore,in this paper,the effect of different gradient roll bonding process and different annealing time on the structure and mechanical properties of 1060 aluminium alloy was investigated by controlling the thickness of each layer in the stack rolled plate to achieve different grain size distribution,using instruments such as metallographic microscope,X-ray diffractometer,scanning electron microscope,micro hardness tester and universal tensile tester.The specimens of 1060 aluminium alloy with good strength and plasticity were selected for the post-rolling annealing treatment,and the tissue and mechanical properties were also observed and tested.The main results of the study are as follows.(1)As the number of rolling passes increases,the interfacial bonding effect gradually improves and the gradient layers show an elongated lamellar structure along the rolling direction.In the single-cycle gradient accumulative roll bonding,the near-surface layers of the specimens change from Copper texture to S texture and Brass texture.In the single-cycle gradient accumulative roll bonding,the near-surface layer of the specimen changes from Copper texture to S texture and Brass texture,while the central layer is mainly Cube texture and a small amount of R-Cube shear texture.In the multi-cycle gradient accumulative roll bonding,the near surface layer of the specimen is mainly R-Cube texture,while the central layer is mainly ?-fibre texture.(2)In the single-cycle gradient accumulative roll bonding,the tensile strength and yield strength of the final sheet increased to 186.3 MPa and 165.5 MPa,while the elongation decreased as a whole,but increased compared with the previous pass.In the multi-cycle gradient accumulative roll bonding,the tensile and yield strengths of the specimens increased and then decreased with the increase of the passes,and the elongation decreased first and then slowly increased,with the best overall mechanical properties of the specimens in the 7th pass,the tensile and yield strengths were 248.3 MPa and 223.0 MPa respectively,and the elongation was 13.3 %.(3)After the stack rolling for different times of low-temperature annealing,will make the plate near the surface and the central layer of the organization,orientation,and will have an impact on the mechanical properties.Multi-cycle gradient accumulative roll bonding,with the increase in annealing time after rolling,each layer of grain alternately recrystallised,the process will occur discontinuous recrystallisation,which is very useful for the formation of gradient structure and performance strengthening.(4)Single-cycle gradient accumulative roll bonding of ARB5 specimens after annealing at 280 °C for 30 min,the tensile strength and yield strength reached 131.7 MPa and 113.2MPa,higher than the strength of the original annealed specimens,while the elongation reached 34.1 %,close to the plasticity of the original annealed specimens,and much higher than the plasticity of the original plate.In the multi-cycle gradient accumulative roll bonding,with the increase of annealing time after rolling,the strength of the 7th pass plate first decreases and then stabilizes,and the elongation increases continuously,and the elongation reaches the maximum of 37 % when annealed at 280 °C for 60 min,at which time the tensile strength and yield strength are 118.8 MPa and 93.1 MPa respectively,and the gradient structure layer after annealing can still improve the stress concentration phenomenon during tension,and the two processes have improved the strength and plasticity of the treated plates in a coordinated manner.