预变形对7N01铝合金力学性能及显微结构的影响

采用力学性能测量和显微结构表征和工艺调控等手段，系统研究了预变形加时效的组合工艺对7N01铝合金力学性能和显微结构的影响.研究表明：与单一的变形强化工艺和单一的时效强化工艺相比，合适的形变时效工艺能大幅提高材料的性能.本实验采用10%预变形后120 ℃再时效，合金的屈服强度可以达到430 MPa，抗拉强度可以达到470 MPa，延伸率仍然保持在14%.随着预变形量的增加，合金的强度先上升后下降，采用过大的变形量反而不利于优化材料力学性能；变形引入的位错会对后续时效强化中纳米析出相颗粒的种类、尺寸和分布等产生关键作用，从而影响材料最终的综合力学性能.
The effect of pre deformation and ageing on mechanical properties and microstructure of 7N01 alloy was investigated by means of process optimization, mechanical property measurement and microstructure characterization. The results show that, compared with single deformation and aging treatment, a suitable combination of pre deformation and thermal aging can significantly improve the mechanical properties of the material. In this study, sample processed with a 10% pre deformation and followed by 120 ℃ aging treatment had the best mechanical property with 430 MPa yield stress and 470 MPa tensile strength, respectively. Meanwhile, the elongation still maintained as 14%. The dislocation introduced during pre deformation played a key role on the types, size and distribution of precipitates in the subsequent aging treatment, which affected the final mechanical properties of the alloys.