镍基合金N06625晶粒长大行为及微观组织形貌

Grain growth behavior and microstructure morphology of nickel-based alloy N06625

对镍基合金N06625进行了固溶处理研究,固溶温度为1 050~1 190℃,保温时间10~70 min,探究了固溶温度和保温时间对晶粒尺寸的影响。通过光学显微镜观察晶粒形貌,电子背散射衍射(EBSD)研究固溶温度对退火孪晶的影响。结果表明:当固溶温度超过1 130℃时,晶粒尺寸开始显著增大,固溶温度超过1 160℃时,晶粒粗化明显;随着温度的升高,Σ3晶界、Σ9晶界和Σ27晶界分数先增大后减小,且在1 080℃下Σ3晶界、Σ9晶界和Σ27晶界分数均达到最大值。根据截线法计算晶粒尺寸,依据温度区间分段建立了Anelli型晶粒长大数学模型。模型预测结果与实验数据进行对比,该数学模型具有较高的预测精度,可为镍基合金N06625晶粒长大提供依据。

The solid solution treatment of nickel-based alloy N06625 was studied at 1050-1190℃and the holding time was 10-70min to investigate the effects of solid solution temperature and holding time on the grain size.The grain morphology was observed by optical microscopy,and the effect of solid solution temperature on annealing twins was investigated by electron backscatter diffraction(EBSD).The results show that the grain size starts to increase significantly when the solid solution temperature exceeds 1130℃,and the grain coarsening is obvious when the solid solution temperature exceeds 1160℃;the fractions ofΣ3 grain boundary,Σ9 grain boundary andΣ27 grain boundary increase and then decrease with the increase of temperature,and the fractions ofΣ3 grain boundary,Σ9 grain boundary andΣ27 grain boundary all reach the maximum at 1080℃.The grain size is calculated by the truncation method,and the mathematical model of Anelli-type grain growth is established based on the temperature interval segmentation.The model prediction results are compared with the experimental data,and the mathematical model has a high prediction accuracy,which can provide a basis for the grain growth of Ni-based alloy N06625.