Eshed Eyal, Shirizly Amnon
Rafael Advanced Defense Systems Ltd., P.O. Box 2250, Haifa 3102102, Israel.
Faculty of Mechanical Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel.
Materials (Basel). 2025 Jul 7;18(13):3198. doi: 10.3390/ma18133198.
In this study, we delve into the intricate microstructural features of Ti-6Al-4V alloy additively manufactured and heat-treated at 800 °C for 4 h. Our in-depth analysis will enable us to gain a better understanding of the β-Ti precipitation process, its dependence on temperature, and its ultimate effect on the overall mechanical properties. As well as α-Ti martensite grains and β-Ti particles interspersed in the α-Ti grain boundaries, there is a third microstructural feature, overlooked by many researchers. This feature is observed as nano-sized particles homogeneously embedded inside the α-Ti laths. Using high-resolution transmission electron microscopy, we reveal that these nano-sized features do not constitute a different phase. Instead, they define isolated regions of α-Ti in its relaxed form, surrounded by the heavily strained form of the α-Ti phase. This phenomenon is a result of the "incomplete" precipitation of the β-Ti phase following the heat treatment stage. The straining of the α-Ti phase appears as a shift in the equilibrium atomic position.
在本研究中，我们深入探究了通过增材制造并在800°C下热处理4小时的Ti-6Al-4V合金的复杂微观结构特征。我们的深入分析将使我们能够更好地理解β-Ti析出过程、其对温度的依赖性以及其对整体力学性能的最终影响。除了α-Ti马氏体晶粒和散布在α-Ti晶界中的β-Ti颗粒外，还有第三个微观结构特征，许多研究人员都忽略了这一特征。该特征表现为均匀嵌入α-Ti板条内部的纳米级颗粒。使用高分辨率透射电子显微镜，我们发现这些纳米级特征并不构成不同的相。相反，它们定义了α-Ti处于松弛形式的孤立区域，周围是α-Ti相的高应变形式。这种现象是热处理阶段后β-Ti相“不完全”析出的结果。α-Ti相的应变表现为平衡原子位置的移动。
