汽车车身用Al-Mg-Si合金薄板织构及r值的研究

采用织构测定分析、TEM观察和拉伸实验研究了退火态、固溶态及T4态汽车车身用Al-0.9Mg-1.0Si-0.7Cu-0.6Mn合金薄板的再结晶晶粒取向、拉伸变形时的晶粒转动规律及其对板材塑性应变比r值的影响.结果表明：具有copper和brass取向的冷轧铝板经410℃×1 h退火或540℃×0.5 h固溶处理后,其再结晶主织构均为绕板法线方向旋转20°的立方取向,即Cube＋ND20,自然时效对再结晶织构无明显影响;单向拉伸过程中主织构Cube＋ND20取向晶粒绕板法线ND向〈100〉方向旋转5°左右,成为Cube＋ND15取向,同时取向密度降低;不同热处理状态铝板在拉伸变形任意应变量时的r值均大致相同.

Study on texture and r values of Al-Mg-Si alloy for automotive body sheets

Orientation of recrystallization grains,behavior of grain rotation induced by plastic deformation,and their effect on the plastic strain ratio r of Al-0.9Mg-1.0Si-0.7Cu-0.6Mn alloy sheets subjected to solid solution,T4 temper and annealing treatment were investigated by texture analysis,TEM and tensile test.The results showed that both copper-type and brass-type textures in cold rolled aluminum alloy sheets are transformed into the recrystallization textures,which consist mainly of cube texture component rotating around the normal direction by 20°,i.e.cube＋ND20 orientation,when the alloy sheets are annealed at 410 ℃ for 1 h or solutionized at 540 ℃ for 0.5 h.Natural aging has little influence on the recrystallization texture of alloy sheets.Grains with main recrystallization texture component Cube＋ND20 rotate around normal direction（ND）,and towards 100 direction by 5° to be changed into Cube＋ND15 orientation with a reduction in orientation density during uniaxial tensile testing.Therefore,the alloy sheets with different heat treatments have an approximately same r values at any strain during tensile deformation.