The Failure Analysts' Mightiest Tool – Thrilling Fractography of Metallic Components

Abstract

Abstract In this contribution, some aspects of fractography are discussed, arguably the failure analysts' most potent analytical tool in metallurgical failure analyses. The characterisation of fracture surfaces is indispensable when it comes to getting to the bottom of things in regards to component failures. When machine parts or entire assemblies fail by fracture of individual members, the fracture surface contains the data that tells the failure analyst about the history of the failed component, and hopefully will also shed some light on the exact failure mode that eventually lead to fracture. That makes fractography, the art of reading fracture surfaces, so valuable. This applies to all material classes, i. e. metals, ceramics, and plastics alike. This paper, however, focuses on failures of metallic components only. When there is no fracture surface in a failed part, one is produced by forcing open cracks or other imperfections that might be suitable for this purpose. Once this is achieved, the failure analyst will open his or her toolset of macro- and microfractographic analysis equipment. It is not exaggerated to say that the scanning electron microscope (SEM) revolutionised the art of microfractography from the early 1960 s on. In this paper, a number of examples for this are given.