摘要
本文通过对两种成分的二元Al-Li合金的硬度测量,DSC分析和TEM观察,研究了其沉淀过程。实验结果表明,在恒定时间时效,合金硬度与温度的关系曲线上在低温范围内有一峰值出现;在DSC曲线低温处有明显的回溶吸热峰,因此该合金低温时效有预沉淀(富Li GP区)形成。在较高温度时效,GP区不复存在;随着δ′相颗粒长大,合金硬度很快增加;DSC曲线上有两个δ′相回溶峰,它意味着δ′析出需有两次结构调整。平衡δ相借助晶界直接从过饱和固溶体中形核长大,其热稳定性较好。
Studies were carried out of the precipitation in two sets of binaryAl-Li alloys by means of hardness test, DSC analysis and TEM observation. Whent healloys were aged for constant time, a peak appeared on the plot of temperaturedependence upon their hardness in the range of low temperature, and the endother-mic dissolution peak was quite distinct on the DSC curve also at low temperature.These are believed that an li-rich GP zone is formed in the alloys aged at lowtemperature, but no more GP zone if aging at elevated temperature. The hardnessof the alloys raises rapidly with coarsening of δ'-phase grains. The two endother-mic peaks of δ' dissolution on the DSC curve are related to the structural adjust-ment at twice of the δ' precipitation. The equilibrium δ-phase, being of higherthermal stability, nucleates and grows directly from the supersaturated solidsolution with the aid of the grain boundary.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
1990年第2期A122-A127,共6页
Acta Metallurgica Sinica
关键词
AL-LI合金
沉淀
时效
回溶吸热
binary Al-Li alloy
precipitation
dissolution
endothermic peak
aging
