热等静压温度对FGH95合金组织及点阵常数的影响

Effects of HIP temperature on microstructure and lattice constant of FGH95 superalloy

通过对FGH95合金进行不同温度的热等静压(HIP)处理、组织形貌观察及XRD谱线分析,研究了热等静压温度对合金组织与平均点阵常数的影响。结果表明,在低于γ'相溶解温度热等静压时,合金中粗大γ'相沿原始颗粒边界区域不连续分布;随热等静压温度提高,合金中粗大γ'相的数量、尺寸逐渐减小;经1180℃HIP后,合金中粗大γ'相完全溶解,晶粒尺寸明显长大。由于γ、γ'两相的平均点阵常数相近,其叠加作用使合金中γ、γ'两相的X射线衍射峰不对称,对不同温度热等静压合金进行XRD谱线测定及分析表明,随热等静压温度提高,合金中γ、γ'两相在室温的平均点阵常数略有增大,而晶格错配度的绝对值略有减小。

Influence of HIP temperature on microstructure and average lattice constant of FGH95 nickel-base superalloy after hot isostatic pressing at different temperatures were investigated by means of SEM and XRD analysis.The results show that the coarser γ′ phase is distributed in the prior particle boundary regions when the HIP temperature is lower than solubility of γ′ phase,and the quantity and size of the coarser γ′ phase distributed in the regions decrease as the HIP temperature is raised.After HIP at 1180 ℃,the coarser γ′ phase in the alloy is dissolved and the size of the grain in the alloy obviously grows up.As a result of the close average lattice constants of the γ′,γ phases in FGH95 alloy,the superposition of the diffraction intensity for γ′,γ phases in XRD patterns results in the asymmetry distribution of the diffraction peaks due to the difference of the volume fraction of γ′,γ phases.It is shown by analyzing XRD patterns of the alloy treated by HIP at different temperatures that the average lattice constants of γ′,γ phases at room temperature increases slightly with increasing HIP temperature,but the absolute values of the lattices misfit decrease.