Intro to Types and Appearances of Fracture

Fracture is the most important and serious type of failure because it can happen suddenly, without warning, and the consequences can be catastrophic. Determining the cause of failure is vital in preventing a recurrence, and the most valuable source of information relating to the cause of a fractured component is the fracture surface itself. In essence, the fracture surface serves as a detailed record of the failure history of the part. A component may fracture or break into two or more fragments that can be examined on the macroscale and on the microscale. Similarly, the fracture surfaces of a cracked component can be parted by sectioning and/or the application of force to permit examination of the fracture surfaces.

This presentation is based on an article to be published in the latest edition of ASM Handbook Volume 12 (Fractography). It provides an overview of visual examination and macroscale fractography, microscale fractography, and the fractography of plastics as compared to metals. The general procedure for fractographic examination is described, along with fundamental rules for interpreting fracture appearances. Numerous fracture surface images and fractographs will be presented to reinforce important points.