B含量对GH4738合金力学性能的影响

Influence of B Contents on Mechanical Properties of GH4738 Alloy

摘要:

通过制备不同B含量的GH4738合金，利用SEM、TEM及EPMA分析研究了B含量对GH4738镍基高温合金持久性能的影响。结果表明，B含量对晶界M₂₃C₆型碳化物的含量及分布有显著的改善作用，提高了晶界M₂₃C₆的析出量和弥散分布的均匀性；B元素主要偏聚于合金中碳化物处，可能作为碳化物形成元素参与碳化物析出；B含量对合金γ′强化相的析出无影响；随着B含量的提高，合金的持久性能不断提高，持久寿命提高了8~12倍，持久塑性提高了2~4倍；持久断裂形式由脆性沿晶断裂转变为混合断裂；B含量对合金拉伸性能影响较小，由于晶粒尺寸的略微增大使合金强度小幅度下降。

Abstract:

The effects of B content on the durability of GH4738 nickel-based superalloy were studied by SEM, TEM and EPMA. The results show that B content can significantly improve the content and distribution of M₂₃C₆ carbides at grain boundaries, and improve the precipitation and dispersion uniformity of M₂₃C₆ at grain boundaries. B element is mainly concentrated in the carbide in the alloy, and may participate in the carbide precipitation as a carbide forming element. The content of B has no effect on the precipitation of γ' strengthening phase. With the increase in B content, the durability of the alloy is improved, the durability life increases by 8?12 times, and the durability plasticity increases by 2?4 times. The permanent fracture mode changes from brittle intergranular fracture to mixed fracture. The effect of B content on the tensile properties of the alloy is small, and the slight increase in grain size results in a slight decrease in the strength of the alloy.