As is known, solidification rate has an obvious effect on microstructure and property. Mechanical properties of Fe-Al-Ta eutectic composites at the solidification rates of 650 μm/s, 700 μm/s, 800 μm/s and 900 μm/s were studied in the present paper. Microhardness, tensile property and fracture toughness of Fe-Al-Ta eutectic composites at different solidification rates were studied respectively. Microhardness value of directionally solidified Fe-Al-Ta eutectic composites is significantly increased as compared with that of the as-cast alloy, and the relationship between microhardness and lamellar/rod spacing satisfies Hall-Petch Formula. There is no obvious plastic deformation characteristic during the process of tensile loading and the eutectic structure fracture is brittle fracture. In addition, the three-point bending fracture toughness is firstly increased then decreased with the increase of the solidification rate. When the solidification rate gets to 700 μm/s, the fracture model of Fe-Al-Ta eutectic composites is a cleavage-dimple mixed fracture, and the fracture toughness reaches the maximum value. The toughening mechanism can be ascribed to fine grain strengthening, crack deflection and interface enhancement.

众所周知，凝固速率对组织和性能有明显的影响。本文研究了凝固速率为 650 μm/s、700 μm/s、800 μm/s 和 900 μm/s 时 Fe-Al-Ta 共晶复合材料的力学性能。分别研究了不同凝固速率下Fe-Al-Ta共晶复合材料的显微硬度、拉伸性能和断裂韧性。定向凝固的Fe-Al-Ta共晶复合材料的显微硬度值较铸态合金显着提高，显微硬度与层状/棒间距的关系满足Hall-Petch公式。拉伸加载过程中无明显塑性变形特征，共晶组织断裂为脆性断裂。此外，三点弯曲断裂韧性随凝固速率的增加先增加后降低。当凝固速率达到 700 μm/s 时，Fe-Al-Ta 共晶复合材料的断裂模型为解理-凹坑混合断裂，断裂韧性达到最大值。增韧机制可归因于细晶强化、裂纹偏转和界面增强。