7A85铝合金时效处理过程中位错密度演变的定量研究

Quantitative Study of Dislocation Density Evolution of 7A85 Aluminum Alloy During the Aging Treatment Process

采用X射线衍射(XRD)和透射电镜(TEM)研究了时效温度和时效时间对位错密度的影响,揭示了7A85铝合金时效过程中位错的演变规律。结果表明,当时效温度从80℃升高到160℃时,位错密度从3.59×10^(14)m^(-2)迅速降低到0.62×10^(14)m^(-2),降低82.7%。同样,随着时效时间的延长,位错密度降低了41%,时效12 h后,位错密度趋于稳定。TEM结果表明,位错倾向于形成低能位错胞,并逐渐向亚晶转变。最后,根据XRD和TEM的结果,分别对位错纠缠态、位错胞和亚晶粒的位错密度进行了量化。

To reveal the dislocation evolution law of 7A85 aluminum alloy during the aging process,the influences of aging temperature and aging time on dislocation density was investigated by X-ray diffraction(XRD)and transmission electron microscopy(TEM).The results show that the dislocation density is reduced rapidly from 3.59×10^(14)m^(-2)to 0.62×10^(14)m^(-2)(decreased by 82.7%)when the aging temperature increases from 80℃to 160℃.Similarly,the dislocation density is decreased by 41%with the extension of aging time,and it tends to a steady value after aging treatment for 12 h.Furthermore,the TEM micrographs indicate that dislocations tend to form a low-energy dislocation cell and gradually turn into subgrain.Finally,on the basis of the results of XRD and TEM,the dislocation densities of dislocation entanglement,dislocation cell and subgrain were quantified.