Influence of B Contents on Mechanical Properties of GH4738 Alloy

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.