What is the difference between fracture and cracking in bending test?

1, fracture means that the material is completely broken under the action of external force, that is, it is completely divided into two parts. Fracture is usually caused by excessive local strain inside the material. Fracture usually produces obvious fracture surface, and two separated surfaces can be seen, and the fracture surface has obvious tensile or shear characteristics. Fracture surface is usually rough, and there may be failure forms such as tearing and perforation.

2. Cracking refers to the cracking of materials under the action of external force, but it is not completely divided into two parts. Cracking usually begins with surface or internal defects of materials, such as cracks and inclusions. Cracking may reduce the strength of the material, but it is not completely broken. Cracks can be fine, linear or branched without obvious fracture.