预变形对Al-Li-Cu-Mg-Zr合金时效析出的影响

EFFECT OF COLD WORKING PRIOR TO AGING ON THE MICROSTRUCTURES IN AN Al—Li—Cu—Mg—Zr ALLOY

通过时效曲线测量和电镜观察,研究了时效前的预变形对一种Al-Li合金时效行为和显微组织的影响。实验结果表明,时效前的少量预变形加速了时效析出过程,促进了S′(Al_2CuMg)相的析出。此外,经过预变形的试样时效后具有较大的时效硬化量,同时具有较窄的晶界无沉淀带。讨论了晶界无沉淀带形成的机理,分析了预变形和时效组织之间的关系。

The effect of cold rolling deformation prior to aging on the aging characte-ristics and microstructures in an Al-Li-Cu-Mg-Zr alloy was studied by hardness measurement and electron microscopy. It is found that a small amount of cold rolling deformation encouraged the homogeneous precipitation of S′phase in the matrix and decreased the widths of PFZ. Age hardening was increased by coprecipitation of S′phase together with δ′phase. Formation of the PFZ has been explained by a vacancy depletion and solute depletion mechanism, and the relationship between pre-deformation and microstructure were also discussed.