Zr含量对镍基粉末高温合金FGH4107平衡相和错配度的影响

Effects of Zr on the equilibrium phases and γ'/γ lattice misfit degree of nickel-based PM superalloy FGH4107

通过真空感应熔炼(VIM)棒料+电极感应熔炼氩气雾化(EIGA)制粉+热等静压(HIP)成形工艺高通量制备5种Zr含量的新型镍基粉末高温合金FGH4107,应用金属材料相图及材料性能模拟软件JMatPro 6.5并结合差示扫描量热分析(DSC)和X射线衍射(XRD),系统研究了Zr含量变化(质量分数0~0.50%)对合金主要平衡相热力学行为、动力学行为以及γ/γ′错配度的影响规律。结果表明:在600~1400℃范围内,Zr含量由0逐渐增加至0.50%时对合金平衡相种类影响不大,均主要由L、γ、MC、MB_(2)、γ′、M_(3)B_(2)、M_(23)C_(6)、μ和σ相组成,Zr原子依次进入γ、γ′、MC和Ni_(7)Zr_(2)相。随着Zr含量增加,合金初熔温度大幅降低而终熔温度仅略微下降,固液两相区温度范围扩大,γ′相完全溶解温度变化不大。添加Zr引起合金γ′相晶格常数加大而γ基体不变,使得合金γ′/γ错配度从0.215%提高到0.265%,表明Zr进入γ′相可增强析出强化效果。

Nickel-based powder metallurgy(PM)superalloy FGH4107 with five varied Zr contents were prepared by the high-throughput preparation,including vacuum induction melting(VIM),electrode induction-melting gas atomization(EIGA),and hot isostatic pressing(as-HIPed)processes.The effects of Zr content(mass fraction 0~0.50%)on the equilibrium phases thermodynamics,kinetic behavior and γ/γ′lattice misfit degree were studied by the calculation and simulation of JMatPro 6.5 software,combined with differential scanning calorimetry(DSC)and X-ray diffraction(XRD).The results show that in the range of 600-1400℃,the Zr content has little effect on the types of equilibrium phases,which are mainly composed of L,γ,MC,MB_(2),γ′,M_(3)B_(2),M_(23)C_(6),μ and σ phases,Zr atoms enter γ,γ′,MC and Ni_(7)Zr_(2) phase in turn.With the increasing of Zr content from 0 to 0.50%,the initial melting temperature is greatly reduced but the final melting temperature is slightly decreased,and the temperature range of the solid-liquid two-phase region is enlarged.However,the Zr content has little effect on the solvus temperature of the γ′phase.With the addition of Zr from 0 to 0.50%,γ′/γ lattice misfit degree increases from 0.215% to 0.265%,indicating that Zr enters γ′phase and enhances the precipitation strengthening effect.