摘要
本文研究了8090型Al—Li合金在190～290℃以及30～200MPa的应力条件下的蠕变断裂行为和蠕变过程中的显微组织变化。实验结果表明,蠕变断裂行为与蠕变过程中发生的沉淀相粗化、平衡相在晶界的析出以及晶界无析出带的宽化等有关。和T_o处理的试样相比,T_8处理试样具有较高的蠕变断裂寿命。这是因为经T_8处理的试样中析出大量S＇相分散了共面滑移,同时能稳定亚晶界阻止动态回复过程因而提高了蠕变断裂阻力。
The creep-rupture behavior of an 8090 type Al-Li alloy was studied at 190-290℃ and at the stresses of 3-20kg/mm^2 The changes of microstructure during creep testing were also investigated. The results indicated that creeprupture life was associated with the coarsing of precipitates, precipitation of equilibrium phases on grain boundaries and the formation of precipitate free zones at the grain boundaries. The specimens had significantly higher creeprupture life in T8 condition than in T6 condition. This was atributed to the fact that precipitates were much more effective in dispersing co-planer slip and delaying dynamic recovery in T8 condition.
