镍铬基K648合金α-Cr相析出的组织敏感性

Microstructure Sensitivity of α-Cr Phase in Ni-Cr Based Alloy K648

研究了合金成分和热处理制度对K648合金组织中α—Cr相析出形态和力学性能的影响，并通过Thermo—calc软件计算了合金的平衡相析出规律。计算结果表明，K648合金中的析出相主要为α—Cr，γ’相和Mzsce碳化物。通过实际组织观察得出合金中α—Cr相的析出形态对Cr含量和热处理工艺制度极为敏感，具体表现为α—Cr相形态的多样性。力学性能测试进一步表明合金的室温拉伸性能、冲击性能均受α-Cr相形态和分布的影响，即合金性能表现出组织敏感性。

The effects of element contents and heat treatment regimes on the precipitation morphology of α-Cr phase and the mechanical properties of K648 superalloy were systemati- cally investigated by room-temperature tension and impact tests. The precipitation law of equilibrium phases in K648 superalloy was calculated by Thermo-Calc software. The calculated results show that the main equilibrium precipitation phases are α-Cr phase, γ＇ phase and M23C6 carbide. Microstructure observations indicate that the precipitation morphology of α- Cr phase is sensitive to the Cr content and heat treatment regime, demonstrating its morpho- logical variety. Mechanical property tests further testify that the room-temperature tensile properties and impact properties are significantly dependent on the morphology and distribu- tion of α-Cr phase, meaning that the mechanical properties of the alloy have microstructure sensitivity.