Al-Cu-Mg合金的预变形、位错密度与位错强化的定量研究

The Quantitative Research of Deformation, Dislocation Density and Dislocation Strengthening in Al-Cu-Mg Alloy

通过拉伸性能测试、X射线衍射仪(XRD)和透射电镜(TEM)分析等方法,研究了Al-Cu-Mg合金的预变形、位错密度与位错强化的定量关系。结果表明:预变形增加了合金热轧板的位错密度,使晶内析出相细小弥散分布,提高了合金的强度,缩短了合金达到峰值时效的时间。采用TEM网格交线法和XRD图谱法测得的位错密度都随着预变形量的增加而增大,增大速率逐渐减小,最终趋于饱和,建立了位错密度与预变形量的函数模型ρ=1.28-1.08e-0.7ε。根据实验数据作出了预变形产生的位错强化随着位错密度的关系曲线图,由此得到了合金热轧板固溶态的位错强化值为67 MPa,占合金固溶态总强度的27%,获得了合金位错强化与位错密度的关系:σd=150ρ1/2 。

The quantitative research of deformation, dislocation density and aging strengthening in Al-Cu-Mg alloy during artificial aging was studied by tensile test, X-ray diffractometry (XRD) and transmission electron microscopy (TEM). The results indicate that the pre-deformation increased the dislocation density of the alloy hot-rolled plate, refined the size of precipitated phase, improved the strength of alloy and reduced the time of peak aging. The dislocation density measured by TEM line intersection method and XRD profile method becomes higher with the increase of predeformation and the increase rate is gradually decreased. Finally it tends to saturation, and the function model of dislocation density and pre-deformation is established:ρ=1.28-1.08e-0.7ε . According to the experimental data, the curve of dislocation strengthening caused by pre-deformation and dis-location density is made, therefore, the dislocation strength of 67 MPa of the alloy hot-rolled plate at solid solution state is obtained, which accounts for 27% of strength of the alloy at solid solution state. And we obtain the relationship between dislocation strengthening and dislocation density: σd=150ρ1/2 .