Industrial fatigue analysis: identifying the origin of a fracture in the laboratory

A fracture of a part can lead to a production stoppage, a quality risk, supplier non-compliance, or a service failure. In this context, a Fatigue analysis makes it possible to reconstruct the fracture scenario, locate the initiation point, identify the propagation modes, and distinguish cyclic loading from an impact, overload, material defect, or interaction with the environment. This approach applies to many matrices: metals, alloys, polymers, elastomers, and composites. It helps manufacturers secure material choices, validate a process, compare a fractured part with an intact one, and guide corrective actions.

Investigations focus on repeated breakages, premature fractures, cracking, surface defects, loss of mechanical performance, corrosion phenomena, or discrepancies between multiple supply sources. The issue may be linked to production, supplier qualification, field returns, a quality dispute, or an R&D program.

For metallic materials, the expertise relies on fracture surface observation using a stereomicroscope and SEM-EDX, chemical composition analysis, Vickers, Brinell, or Rockwell hardness measurement, as well as metallographic examination under an optical microscope. Depending on the need, techniques such as ICP, elemental analysis C/S, N/O, H, or surface analysis may be carried out to verify the grade, look for oxidizing elements, or characterize corrosion.

Specialized expertise makes it possible to turn an observed breakage into a well-supported technical diagnosis. The expected result is not just an observation, but an understanding of the failure mechanism, a prioritization of the most likely causes, and useful input for correcting a design, a process, a material choice, or a service condition.

The laboratory supports manufacturers in fracture surface analysis and in characterizing the causes of failure. The approach combines fractographic observation, composition testing, microstructure examination, hardness measurements, and the search for external agents that may promote corrosion, embrittlement, or mechanical damage. This expertise makes it possible to characterize a brittle, ductile, or fatigue fracture, highlight a material or surface non-conformity, and establish correlations between the condition of the part, its environment, and its loading history.

The analysis makes it possible to identify a brittle, ductile, or fatigue fracture, to highlight a material defect, a heat treatment anomaly, an unsuitable grade, microstructural heterogeneity, an inclusion, a coating defect, wear by friction, a crack initiated at the surface, or the effect of a corrosive agent. To investigate certain cases further, additional examinations such as the Laboratoire Analyse Meb, the Analyse Inclusion Laboratoire, or the Laboratoire analysis Met may be used.

For polymers, elastomers, and composites, the investigation may combine IR microscopy, FTIR-ATR, DSC, TGA, Py-GC/MS, GPC/SEC, NMR, SEM-EDX, and rheological analysis in order to identify the material, additives, fillers, crosslinking rate, crystallinity, or aging markers. In the event of a fracture linked to thermal behavior or aging, a Analyse De Polymeres Par Atg En Laboratoire can usefully complement the expertise.

The value of a laboratory with cross-disciplinary expertise in materials, surfaces, and analytical chemistry is its ability to connect the clues observed on the fractured area to their true cause: mechanical fatigue, corrosion, external contamination, treatment defects, composition deviations, or surface defects. This approach can also be complemented by testing or characterization standards such as Laboratoire Analyse Iso 21392 when the project context requires it.

To begin the investigation, it is recommended to send the fractured part, if possible a non-fractured reference part, the operating conditions, the failure history, the known mechanical loads, the service environment, and any available material specification. Based on these elements, the laboratory defines an analysis strategy suited to the level of urgency, the criticality of the application, and the material involved.