摘要
研究经不同轧制预变形处理(0~20%)后2050 Al−Li合金T8时效状态的显微组织演变和力学性能。通过透射电子显微镜(TEM)和扫描电子显微镜(SEM)对其显微组织进行表征。结果表明:随着预变形量的增加,晶粒尺寸沿ND方向显著变小,晶内畸变增大。位错等的缠结为T1相的析出提供了大量的形核位点。这导致析出相数量增多,析出相之间的距离缩小,从而提高了对位错运动的阻碍作用和合金强度。当预变形量为16%时,T1相数量密度和合金强度最高(屈服强度和抗拉强度分别达到568和584 MPa,伸长率为8.6%);当预变形量进一步增加到20%时,由于位错缠结,原子扩散通道减少,T1相数量的减少最终导致合金强度降低。
The microstructural evolution and mechanical properties of 2050 Al−Li alloy subjected to different rolling pre-strains(0−20%)and aging(T8)were studied.Transmission electron microscopy(TEM)and scanning electron microscopy(SEM)were used to characterize the microstructure.The results show that the grains were significantly refined along the normal direction(ND)and the intragranular distortion increased with the increase of pre-strain level.The entanglement of defects,e.g.,dislocations,provides a large number of nucleation sites for the precipitation of T1 phases.This leads to larger number of precipitates and narrower distance between precipitates,thus improving the hindering effects on dislocation motions and the strength of the alloy.When the pre-deformation level reaches 16%,the alloy shows the highest density of T1 phases and strength(the yield strength and tensile strength reach 568 and 584 MPa,respectively,and elongation is 8.6%).When the amount of pre-deformation is further increased to 20%,the atomic diffusion channels are reduced due to dislocation entanglement,and the reduction in the number of T1 phases eventually leads to a decrease in strength of the alloy.
作者
李耀
徐国富
乔海光
刘时超
彭小燕
Yao LI;Guo-fu XU;Hai-guang QIAO;Shi-chao LIU;Xiao-yan PENG(School of Materials Science and Engineering,Central South University,Changsha 410083,China;Key Laboratory of Nonferrous Metal Materials Science and Engineering,Ministry of Education,Central South University,Changsha 410083,China)
基金
supported by the National Key Research and Development Program of China (No.2018YFB2001801)
the National Key Project of Research and Development Plan (No.2021YFC1910505)
the Hunan Provincial Natural Science Foundation of China (No.2020JJ5742)
the Key Research and Development Program of Guangdong Province,China (No.2020B010186002).
