SEM and Failure Investigations
An SEM, or scanning electron microscope, is a type of microscope that produces images of a sample by scanning the surface with a focused beam of electrons rather than the usual optical means. This allows for imaging at very high magnifications, typically from about 10 to 500,000 times, with a clarity previously not possible.
Typical features that can be viewed are fracture faces of failed parts, or surface conditions of components.
EDX, also variously known as EDAX or EDS, EDX microanalysis is the targeted analysis of a feature observed on the scanning electron microscope. The method is limited in that it is semi-quantitative, cannot identify organic matter and there are a few elements that it cannot detect, even if present, but if you have an unknown material (for instance, contamination on a component or a fracture face) EDX can be used to identify its approximate chemical make-up.
SEM or EDX can be used on a failed component that’s made from metal. From domestic copper pipework, fastener systems (or nuts and bolts), high-tension wires, chains, cast housings, even artificial hip implants; in truth the scope is limited only by the ability of metal to be used in an application.
Should a part fail, Manufacturers and consumers need to know how and why. A failure investigation that includes SEM/EDX can provide answers to why a part has failed. Steps can then be taken to help avoid the same problem & issues in future and therefore reduce costs & expenses.
Examples of the causes of failures include but are not limited to, design flaws, material selection, raw material issues or misapplication of the component.
Failure Investigations consist of individual tests that include a visual examination, SEM (and EDX if required), metallography, chemical analysis, hardness test and tensile tests, subject to sufficient sample material being provided.