淬火温度对U-2.5wt% Nb合金组织及力学性能的影响

Effect of Quenching Temperature on the Microstructure and Compression Behavior of U-2.5Nb Alloy

摘要: 开展了不同热处理状态下U-2.5wt% Nb （U-2.5Nb）合金的静动态力学性能实验，利用金相显微镜、X射线衍射、扫描电镜等手段研究了淬火温度对U-2.5Nb合金显微组织结构的影响.结果表明：随着淬火温度（800℃至620℃）不断降低，U-2.5Nb合金的显微组织和相结构发生显著变化，由含铌的过饱和α'单相斜方结构过渡为α+γ₂双相结构.强度随淬火温度降低而下降，而塑性显著增加.压缩载荷下，655℃（α+γ₁双相）快速淬火处理后的屈服强度最低，这可能是由于γ₁相是富铌相，该温度下快速淬火的组织中α″相较高所导致的.

Abstract: The compression behavior of U-2.5wt%Nb (U-2.5Nb) alloy with different heat treatment condition was investigated. The microstructure and phase composition were analyzed by OM, XRD and SEM. Results show that the microstructure and phase composition are closely related to the quenching temperature. With the quenching temperature decreased from 800℃ to 620℃, the nb-containing supersaturation monoclinic evolved into α+γ₂ two-phase. The yield strength decreased with decreasing quenching temperature, while the ductility increased significantly. The 655℃ quenched specimen exhibited the lowest yield strength, which may be related to the considerable content of α″ phase obtained by quenching of γ₁ phase.