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针对700℃先进超超临界电站过热器/再热器管用镍基高温合金Inconel 740H,通过热力学相计算研究了主要析出强化元素对其平衡析出相析出行为的影响.结果表明:合金中γ′相和M23C6碳化物稳定温度范围宽,稳定性好;Al、Ti和Nb 3种合金成分对γ′相、η相和σ相的析出和稳定性影响大,而Co的影响不大,其中Al对γ′相和σ相的析出和稳定起促进作用,对η相起抑制作用,Ti和Nb对γ′相、η相和σ相均起促进作用;C显著影响M23C6碳化物的析出量,Cr显著影响M23C6碳化物的析出温度.Al、Ti和Nb的质量分数分别控制在1.2%～1.4%、1%～1.5%和1%～1.6%为宜;同时,C的质量分数保持在0.05%左右,Cr的质量分数也应保持25%左右,Co的质量分数有所减小,不会影响γ′相和M23C6碳化物等强化相的析出量,从而对Inconel 740H合金的成分范围进行了一定的优化.
Aiming at the Inconel 740H nickel-base superalloy of superheater / reheater tube at 700 ℃ in advanced supercritical power station, the influence of main precipitation strengthening elements on the precipitation behavior of equilibrium precipitates was studied by thermodynamic phase calculation.The results show that the γ ’phase And M23C6 carbides have stable temperature range and good stability. Al, Ti and Nb alloying compositions have great influence on the precipitation and stability of γ ’phase, η phase and σ phase, while the effect of Co is not significant, The precipitation and stabilization of γ ’phase and σ phase are promoted, while η phase is inhibited. Ti and Nb promote the γ’ phase, η phase and σ phase. C significantly affects the precipitation of M23C6 carbide, Significantly affect the precipitation temperature of M23C6 carbide.The mass fraction of Al, Ti and Nb are respectively controlled at 1.2% ~ 1.4%, 1% ~ 1.5% and 1% ~ 1.6%, while the mass fraction of C is maintained at 0.05% , The mass fraction of Cr should be kept at about 25%, the mass fraction of Co is reduced, the precipitation amount of strengthening phase such as γ ’phase and M23C6 carbide will not be affected, so the composition range of Inconel 740H alloy is constant Optimization.