Microstructure And Mechanical Properties Of 6016 Aluminum Alloy Sheet By Equal Channel Angular Rolling

Aluminum alloy as an ideal light-weighting material should be widely applied to substitute steel in car body components to reduce fuel consumption and CO2-emissions.However,the current body with 6××× aluminum alloy forming performance is poor,strong anisotropy,especially the plastic strain ratio r value is small.It is one of the major problems that obstacle 6××× aluminum large-scale application.In this paper,6016 aluminum alloy as the research object,from the change of plastic processing technology to start,through the equal angle rolling process to control the composition and content of texture,so as to achieve the purpose of weakening the texture to improve the forming performance.With the quasi-static uniaxial tensile experiment,Cup test,optical microscopy（OM）and XRD macro texture methods,The difference between the microstructure and the mechanical properties were analyzed by comparing the equal channel angular rolled sheet with the conventional rolled sheet.The effects of three parameters of rolling path,mold channel angle and sheet preheating temperature on the microstructure and mechanical properties of the plate were studied.The conclusions can be summarized as follows:（1）By equal channel angular rolling,the deformation textures of sheet can be scattered and the recrystallization textures can be weakened,and the anisotropy can be weakened,and the forming performance of the sheet can be improved.Compared with the conventional rolling,the volume fraction of the S texture of the RT sample is very low,and the elongation,the （?） value and the IE value of the T4 P sample are much higher than those of the conventional rolling plate.Equal channel angular rolling has lower yield strength and Δr value,but has better forming properties than conventional rolling.（2）The rolling path mainly affects the cumulative strain degree of the plate with equal channel angular rolling.Compared with the AB path,the cumulative strain of the plate under the AA path is higher,the texture of the β-oriented line in the RT sample is weaker,the Cube texture in the T4 P sample is weaker,and there is a small amount of weak {441}<2（?）4>,{210}<001> and other textures,the forming performance is better,the anisotropy is smaller.（3）The angle of the mold channel mainly affects the shear strain and the lattice rotation degree of the plate with equal channel angular rolling.The grain size of T4 P sample gradually increases,and the uniformity of thick distribution gradually increases with the angle rising from 120° to 135° and to 150°.Along with 135o as angle,The textures of the β-oriented lines in the RT sample are weak,and the Cube textures of the T4 P plate are weak,and there are small amount of {023} <100>,{212} <（?）4> and so on.The T4 P sample has better forming properties and smaller anisotropy.（4）The forming properties of T4 P sample increasesed with the temperature rising from 20℃ to 420℃.When the preheat temperature arrives at 420℃,the RT sample is dynamicallyrecrystallized,and deformed textures still exists in the sheet but the intensity and volume fraction are pretty low.With this temperature condition,there are small amount of intermediate state textures converting to recrystallization textures.And the T4 P sample have a little P{011}<112>,Goss{110}<001> textures and some unusual textures featuring low intensity and disordered distribution but no strong recrystallization textures.Along with 420℃ as preheat temperature,the T4 P sample shows good elongation（δ>29%）,and formability(σ_0.2<110MPa,（?）≈0.75,Δr≈0.16),while T8 X sample owns good bake hardening response(σ_0.2 >210MPa,σ_b>335MPa).