Abstract Ti–48Al–2Cr–2Nb (Ti4822) alloy was manufactured by the electron beam melting (EBM) process, and its microstructure and compressive deformation behavior at room and high temperatures (25, 600, 750, 900, and 1050 °C) were investigated. In addition, plasma-melted Ti4822 alloy was manufactured as a reference material to compare the microstructure and mechanical properties. EBM-built Ti4822 has a near-gamma structure composed of equiaxed γ phase (L10 structure) with α2 (D019 structure) phase at the interface of γ phase, whereas plasma-melted Ti4822 has a fully lamellar structure. Temperature-dependent compression tests identified that EBM-built Ti4822 has relatively low yield strength in all temperature ranges compared to plasma-melted reference material. However, in the case of ductility, EBM-built Ti4822 has higher fracture strain compared with plasma-melted Ti4822. The reason for this behavior is the microstructural differences found between EBM-built and plasma-melted Ti4822. In the high-temperature compressive results, yield stress anomaly (YSA) phenomena occurred in a certain temperature range with both alloys. The room temperature deformed microstructure shows that EBM-built Ti4822 accommodated deformation by dislocation glide and twinning, while plasma-melted Ti4822 could not fully accommodate the deformation. In addition, dynamic recrystallization (DRX) occurred at above 900 °C in the EBM-built Ti4822, and above 750 °C in the plasma-melted Ti4822, suggesting that different DRX behavior appeared in high temperature deformation. Based on the above findings, this study further analyzed the correlation between the microstructure and the room- and high-temperature deformation mechanism of EBM-built Ti–48Al–2Cr–2Nb.

中文翻译：

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电子束熔化增材制造γ-TiAl基Ti-48Al-2Cr-2Nb合金的高温压缩变形行为

摘要 Ti-48Al-2Cr-2Nb (Ti4822) 合金采用电子束熔炼 (EBM) 工艺制造，及其在室温和高温（25、600、750、900 和 1050 °C）下的显微组织和压缩变形行为被调查。此外，还制造了等离子熔化的 Ti4822 合金作为参考材料，以比较显微组织和机械性能。EBM 构建的 Ti4822 具有近伽马结构，由等轴 γ 相（L10 结构）和 γ 相界面处的 α2（D019 结构）相组成，而等离子熔化的 Ti4822 具有完全层状结构。与温度相关的压缩测试表明，与等离子熔化的参考材料相比，EBM 制造的 Ti4822 在所有温度范围内都具有相对较低的屈服强度。但是，在延展性的情况下，与等离子熔化的 Ti4822 相比，EBM 制造的 Ti4822 具有更高的断裂应变。这种行为的原因是在 EBM 构建的 Ti4822 和等离子熔化的 Ti4822 之间发现的微观结构差异。在高温压缩结果中，两种合金在一定温度范围内均出现屈服应力异常（YSA）现象。室温变形显微组织表明，EBM 构建的 Ti4822 通过位错滑移和孪晶适应变形，而等离子熔化的 Ti4822 不能完全适应变形。此外，EBM构建的Ti4822在900°C以上发生动态再结晶（DRX），等离子体熔化的Ti4822在750°C以上发生动态再结晶（DRX），表明在高温变形中出现了不同的DRX行为。基于以上发现，