【摘要】 应用透射电镜研究了2091 Al-Li 合金T₆,T₈不同时效处理后的显微组织,并讨论了不同组织对性能的影响。指出在两种处理中δ′相和晶界无析出区（PFZ）的长大均与时效时间的1/3次方成正比,而预应变加速了它们的生长。另外预应变促使 S′、T₁相形核,使其均匀细小地分布在 Al基体和晶界附近δ′的无析出区中,从而使合金在较短时间达到更高的强度峰值。在 T₆48小时处理的合金中观察到 T₂相,通过衍射,高分辨象确定为五次对称准晶相。更多还原

【Abstract】 Microstructures and corresponding properties of 2091 AL-Li alloy after T6 and T8 aging treatments was investigated by TEM technique,The results sh- owed that the Linear dimension of the δ′phase and the precipitates free zone （PFZ） were proportional to t^1/3,where t is aging time However,prestrain accelerates growth speed of both the δ′ phase and pFZ,induced the nuclea- tion of the S′,T1 phases,and brought out the uniform distribution of these fine precipitates in the matrix and specially in the δ′ PFZ.Therefore,the strength of the alloys could approach to a higher peek value. A T2 phase has beeu also observed in the sample after a T6 treatment for 48 hrs,which can be determined as the icosahedral quasicrystal phase by means of electron diffraction and high resolution imaging.更多还原