Fracture analysis

Fracture analysis includes macro analysis and micro analysis. Macroscopic analysis only needs the help of magnifying glass and low power microscope, which can be used to observe and analyze the fracture surface at low power, and obtain the general features of the fracture surface, so as to understand the causes of failure to a certain extent; Micro analysis is based on the macro analysis, through the electronic microscope and other instruments to further find out the fracture path, nature, environmental media and temperature on the impact of fracture, and further determine the cause and mechanism of fracture and other details.

Test items and equipment

Macroscopic fracture analysis

Through macro fracture analysis, we can judge the nature of fracture and the whole process of fracture accident, and put forward goals and tasks for further micro fracture analysis. Macro fracture analysis is the premise and foundation of micro fracture analysis.

Testing equipment: reading microscope, stereomicroscope

Micro fracture analysis

The microscopic analysis of fracture surface is realized by optical microscope and scanning electron microscope. Due to the limitation of the depth of field, optical microscope can only observe the cleavage fracture and fatigue fracture roughly, but can not observe the transgranular fracture and intergranular fracture with obvious plastic deformation. Even for the flat fracture, it is difficult to carry out large-area continuous observation, and the resolution is low. However, optical microscope can be used to analyze some structures of fracture surface with polarized light, and observe the color changes of different areas of fracture surface, which plays an important role in the diagnosis of fracture properties. SEM has a large depth of field, which can study the rough fracture surface and obtain clear images. The magnification can be changed continuously from 10 times to 100000 times, which is convenient to observe the fracture details.

Testing equipment: metallographic microscope, scanning electron microscope