Bovine hoof wall with an alpha keratin structure, as the interface between the ground and the body, can protect the bony skeleton from the impact and the destruction. Microstructure and mechanical properties of the bovine hoof wall are investigated by scanning electron microscope (SEM), transmission electron microscope (TEM) and quasi-static mechanical tests. Mechanical results show that the mean J-integral values of the LD specimens parallel to the tubular axis are higher than those of the TD specimens normal to the tubular axis, and the fracture toughness reaches the peak values (21 kJ/m², 33 kJ/m² for the TD and the LD specimens, respectively) at 16.5% moisture content. The morphology results show that the laminated keratin structure can form the extensive strain-transition interfaces and the tubules played an important role in twisting crack propagation. Angles of the laminated structures within the inter-tubular materials are not a uniform distribution varying from 0° to 90° against to the tubular axis. The interlocking interface in the tubular structure can provide increased the contact area and contribute to the bonding strength between the layers. We also propose models to illustrate the morphological structure and the crack propagation mechanism of the bovine hoof wall. This structure with the strong fracture resistance ability will provide a new inspiration for design of structural materials and architectures.

牛蹄壁具有alpha角蛋白结构，作为地面与身体之间的界面，可以保护骨骼免受撞击和破坏。通过扫描电子显微镜（SEM），透射电子显微镜（TEM）和准静态力学测试研究了牛蹄壁的微观结构和力学性能。机械结果表明LD标本平行于管轴线的平均J积分值比的TD的更高标本垂直于管轴线，并且断裂韧性达到峰值（21千焦/米²，33千焦/米²对于TD和LD样品，水分含量分别为16.5％。形态学结果表明，层状角蛋白结构可形成广泛的应变转变界面，并且小管在扭转裂纹扩展中起重要作用。管间材料内的层压结构的角度不是相对于管轴从0°到90°变化的均匀分布。管状结构中的互锁界面可提供增加的接触面积并有助于层之间的粘合强度。我们还提出模型来说明牛蹄壁的形态结构和裂纹扩展机理。这种具有较强抗断裂能力的结构将为结构材料和建筑设计提供新的启示。