新型热机械处理对Al-Cu-Mg合金微观组织与综合性能的影响

研究了新型热机械处理工艺参数对Al-Cu-Mg合金微观组织与综合性能的影响。结果表明，经过新型热机械处理的Al-Cu-Mg合金可以达到良好的强塑性配合，采用15%非对称轧制压下量和100 ℃ × 24 h的低温人工时效工艺时，合金抗拉强度和屈服强度分别达到515.9 MPa和426.3 MPa，延伸率达到11.6%。新型热机械处理可以显著改变Al-Cu-Mg合金的晶粒取向，合金织构演变过程包括立方织构和高斯织构的形成和转变、黄铜织构和铜织构等轧制织构的形成以及非对称轧制引入的剪切织构。合金疲劳裂纹扩展性能与晶粒取向密切相关，固溶热轧处理引入的高强度高斯织构与非对称轧制引入的剪切织构导致疲劳裂纹偏折，从而使合金获得更好的抗疲劳裂纹扩展性能。

Effect of Novel Thermomechanical Treatment on Microstructure and Comprehensive Properties of Al-Cu-Mg Alloy

The effect of a novel thermomechanical treatment (NTMT) on the microstructure and comprehensive properties of Al-Cu-Mg alloy were investigated. The Results show that the alloy treated by NTMT can obtain an excellent combination of strength and ductility. With 15% asymmetric rolling reduction and 100 ℃×24 h low-temperature artificial aging, the ultimate tensile strength and yield strength reach 515.9 MPa and 426.3 MPa respectively, while elongation reaches 11.6%. It is shown that this NTMT can significantly change the grain orientation of Al-Cu-Mg alloy, and the evolution of alloy texture includes the formation and transformation of cube texture and Goss texture, the formation of rolling textures like brass and copper textures, and the introduction of shear textures by asymmetric rolling. Fatigue crack growth (FCG) property of the alloy are closely related to the grain orientations. The high intensity Goss texture introduced by solution treatment - hot rolling - quenching process and shear texture introduced by asymmetric rolling result in the fatigue crack deflection, which make the alloy with better FCG resistance.