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采用等温热压缩实验,通过计算和对比热激活参数,并利用EBSD和TEM分析技术,研究了2099合金在热变形过程中的动态软化机制.基于Zener-Hollomon参数(Z)和变形温度(T)并结合对热激活参数与微观组织的分析,给出了2099合金在热变形中的软化机制.在lnZ≥35.5和T≤380℃范围内,变形以位错的交滑移为主.在lnZ≤37.4和T≥340℃范围内,由位错的交滑移、攀移以及三维位错网脱缠等变形机制共同控制.在lnZ≤35.1和T≥420℃范围内,发生了动态再结晶,此时以位错的交滑移、攀移、动态再结晶以及位错的脱钉为主要软化机制.动态再结晶形核机制以晶界弓出和亚晶合并共存,并随着变形温度的升高和应变速率的降低,亚晶合并形核得到强化.
By means of isothermal hot compression experiments, the dynamic softening mechanism of 2099 alloy during hot deformation was studied by means of calculating and comparing the heat activation parameters and using EBSD and TEM analysis. Based on the Zener-Hollomon parameters (Z) and deformation temperature (T ) And combined with the analysis of thermal activation parameters and microstructure, the softening mechanism of 2099 alloy during hot deformation is given. The deformation is dominated by the cross-slip of dislocation in the range of lnZ≥35.5 and T≤380 ℃ In the range of lnZ≤37.4 and T≥340 ℃, the deformation mechanisms such as dislocation cross-slip, climbing and three-dimensional dislocation network unwinding are jointly controlled.In the range of lnZ≤35.1 and T≥420 ℃, The main softening mechanism is dislocation slip, climbing, dynamic recrystallization and dislocation of the dislocations.The dynamic recrystallization nucleation mechanism coexists with the grain boundary bowing and subgrain coalescence, and with the deformation As the temperature increases and the strain rate decreases, the nucleation of subgrains is strengthened.