The Research Of The Thermal Stability And Mechanical Properties On The Ni-Fe Base Superalloy GH2107

GH2017 is an Ni-Fe based wrought superalloy, it not only has a good plastic toughness and thermal fatigue resistance, but also has an excellent stress rupture properties, it is mainly used in the work of 700-750℃ gas turbine power station. GH2107 is based on the GH2135 by reducing 2% of Al+Ti. It does not contain heavy metal elements besides adding Fe so that saving a lot of cost. The paper is mainly talk about the effect of temperature and time on the microstructural evolutions during long term thermal exposure that under the condition of 650,700and750℃ ageing 500-10000 h. Also carried out the tensile test and creep test of the standard heat treatment alloy. Finally, discussing the effects of B and P microalloying on microstructure and mechanical properties of the alloy. The main conclusions follows:The major precipitates in the alloy were spherical γ′, M23C6 and MC carbide. During thermal γ′ and grain boundary coarsened with increasing the exposure time and exposure temperature which is the most severe in 750℃. However, after exposure at 750℃ up to 3000 h or 700℃ up to 5000 h, small amount of block-like or piece-like TCP phase precipitated at grain boundary, around carbides and matrix.The tensile test show that: The fracture mechanism is from intergranular to transgranular when temperature is from room to high, the yield strength has a significant rebound in 700℃. The LMP curves of the creep test showing an excellent rupture property which can reach 100000 h at 200 MPa.B and P play a significant role in strengthening grain boundaries at 700 ℃ than room temperatures, improving mechanical properties of the alloy. But, high content of B impair the beneficial effect of P element, reducing the tensile strength and stress rupture life of the alloy. P will suppress crack initiation and propagation in the surface, benefiting for the stress rupture.