Fractography is a technique used (especially for metals) for studying the cause of failure of a particular part with the help of high resolution photographs of fractured surfaces.
The focus of fractographic investigation is to study the cause of failure by observing the origin of a crack or fracture in the part due to various reasons like inclusions of voids or foreign materials, points of stress concentrations etc.
Fractography is widely used with fracture mechanics to understand the causes of failures and also to verify the theoretical failure predictions with real life failures.