Re及温度对单晶镍基合金晶格常数及错配度的影响

Influences of Element Re and Temperatures on the Lattice Parameter and Misfit of Single-Crystal Nickel-Based Superalloys

摘要:

通过对不同状态及不同Re含量单晶镍基合金进行高、低温X射线衍射谱线测定及组织形貌观察，研究Re含量及温度对单晶镍基合金中γ、γ′两相晶格常数及错配度的影响。结果表明：铸态合金中γ、γ′两相有较大的晶格常数及错配度；经完全热处理后，立方γ′相以共格方式嵌镶在γ基体中，合金中两相的晶格常数及错配度略有减小；长期时效使γ′相粗化后，两相之间出现界面位错，使合金中两相的晶格常数及错配度绝对值增加。随Re含量增加，合金中γ、γ′两相在室温的晶格常数增大，错配度的绝对值减小。与γ′相相比，γ基体相有较大的膨胀系数，因此，随温度提高，合金中两相晶格错配度的绝对值增大

Abstract:

By means of X-ray diffraction analysis at different temperatures and microstructure observation, an investigation has been made on the influence of element Re and temperatures on the lattice parameter and the misfit of single-crystal nickel based superalloys. Results show that the bigger lattice parameter and misfit are displayed in as-cast superalloy. After fully heat treatment, the cubic g ￠ phase is coherently embedded in the g matrix phase, and the lattice parameters and misfit of g ￠ and g phases are slightly reduced. After aged for long time, the coarsening of g ￠ phase in the alloy occurs, and the interfacial dislocations appear between g ￠ and g phases, which increases the parameters and the absolute misfit of g ￠ and g phases. The lattice parameters of g ￠ and g phases in the alloys at room temperature increase with the element Re increasing, and the absolute values of the misfit decrease. Compared with the g ￠ phase, the g matrix phase displays a bigger dilation coefficient; therefore, the lattice parameters and the absolute misfit value of g ' and g phases in the alloy increase with the temperature increasing