Two samples of an α + β Ti-4Al-4Mo-4Sn-0.5Si (wt%) alloy, one with fine prior β grains and a heterogeneous microstructure and the other with coarse prior β grains and a homogeneous microstructure were prepared by extrusion of compacts of TiH₂/Al/Mo/Sn/Si powder blend at 1200 and 1300 °C respectively. The heterogeneous microstructure is manifested by softer Mo-rich regions with a full α/β lamellar structure containing a high number density of parallel and nanometer sized FCC δ (TiH) needles in a harder matrix with a microstructure consisting of interweaved α plates and β transformed structure (β_t) domains and grain boundary α (GB α) layers. The matrix also contains a small fraction of Sn-rich regions which have the same microstructure as the matrix. The Mo-rich and Sn-rich regions form due to the limited diffusion of Mo and Sn alloying elements. This heterogeneous microstructure sustains a high tensile yield strength of 1199 MPa, a high strain hardening rate, and an excellent tensile ductility of 12.0%. In contrast, the homogeneous microstructure comprising of interweaved α plates and β_t domains together with GB α layers sustains a similar high strength, but a clearly lower strain hardening rate and a significantly lower tensile ductility of 3.5%. Non-homogeneous deformation capacity, the release of energy by forming numerous microcracks and the intermittent growth of microcracks of the heterogeneous microstructure suggest that this microstructure has a high plasticity and high resistance to the growth of microcracks.

α + β Ti-4Al-4Mo-4Sn-0.5Si (wt%) 合金的两个样品，一个具有细的原始 β 晶粒和不均匀的显微组织，另一个具有粗大的原始 β 晶粒和均匀的显微组织。 TiH ₂ /Al/Mo/Sn/Si 粉末混合物的压块分别在 1200 和 1300 °C。异质微观结构表现为较软的富钼区域，具有完整的 α/β 层状结构，包含高数量密度的平行和纳米尺寸的 FCC δ (TiH) 针，在较硬的基体中，微观结构由交织的 α 板和 β 转变结构 (β _t) 域和晶界 α (GB α) 层。基体还包含一小部分与基体具有相同微观结构的富锡区域。由于 Mo 和 Sn 合金元素的有限扩散，形成了富钼和富锡区域。这种异质微观结构保持了 1199 MPa 的高拉伸屈服强度、高应变硬化率和 12.0% 的优异拉伸延展性。相比之下，由交织的 α 板和 β _{t组成的均匀微观结构}域与 GB α 层一起维持类似的高强度，但应变硬化率明显较低，拉伸延展性显着降低 3.5%。非均质变形能力、形成大量微裂纹的能量释放以及非均质微裂纹的断续生长表明该微结构具有高塑性和高抗微裂纹生长能力。