Effect Of Deformation And Annealing Process On Structure And Properties Of Al-0.2wt.%Zr Alloy

As an element that can effectively improve the comprehensive properties of aluminum alloy,zirconium has become an indispensable element in many aluminum alloys.The correlation research indicated,the existence of various forms of Zr in the aluminum matrix under different solidification and heat treatment conditions,the influence of various Zr existing forms on the comprehensive properties of aluminum alloys still needs to be studied systematically.Under the previous research work(cast of high Zr solid solution Al-Zr alloy)of our workgroup,The effects of different homogenization annealing systems on the recrystallization behavior of cold-rolled Al-0.2wt.%Zr alloy sheet were studied in order to study the effect of different forms of Zr on the properties of commercial aluminum.The main contents of this paper are as follows:(1)Effect of homogenization annealing on microstructure and properties of Al-0.2wt.%Zr alloy.(2)Effect of different homogenization annealing regimes on the recrystallization behavior of Al-0.2wt.%Zr alloy.Research results show that:(1)Under different homogenization annealing process(425?,475?,525? for 24 hours),a large number of nanoscale near spherical Al3Zr phase is precipitated in the matrix of aluminum alloy.With the increase of the annealing temperature,the number of precipitated phases increased,conductivity and hardness are also increased.The conductivity increased from 54.0%IACS(as-cast)to 57.4%IACS(525? for 24 hours);the hardness increased from 25.1HV3(as-cast)to 29.1HV3(525? for 24 hours).(2)After total deformation of 92.8%,the cold rolling microstructure along the rolling direction of Al-0.2wt.%Zr alloy sheet and commercial aluminum sheet are fibroid.The hardness of the specimens after cold rolling was significantly increased to 65.6-68.7HV3,conductivity decreased within 1.8%.(3)Under different homogenization annealing system(425?,475?,525? for 24 hours),the addition of Zr significantly increased the recrystallization start temperature and the end temperature of the cold-rolled commercial aluminum sheet.The recrystallization starting temperature of the cold-rolled Al-0.2wt.%Zr sheet under homogenization annealing is 400?,the recrystallization end temperature is 450-500?.(4)The effect of addition of 0.2wt.%Zr on the recrystallization temperature of cold-rolled industrial pure aluminum is limited under no uniform annealing,and the recrystallization starting temperature of industrial pure aluminum cold-rolled sheet is 350? and the final temperature is 450?.(5)A large number of A13Zr phase precipitated in the matrix increases the recrystallization temperature of the cold-rolled Al-0.2wt.%Zr plate under no annealing before rolling and 350? for 24h after rolling,the recrystallization temperature of specimens is 400?,and the end temperature is 500?.(6)The recrystallization temperature of commercial aluminum can be improved remarkably by the Zr element in the form of nanometer Al3Zr precipitation phase,while the Zr element in the form of solid solution has limited effect on the recrystallization of commercial aluminum.