Failure analysis laboratory: identifying the origin of industrial breakage

Une casse industrielle peut avoir des consequences immediates sur la production, la securite, la conformite produit et les couts de maintenance. Lorsqu’une piece rompt, l’enjeu n’est pas seulement de constater la defaillance, mais de determiner avec precision l’origine d’une casse : surcharge ponctuelle, fatigue mecanique, choc, deformation excessive, corrosion, pollution externe, defaut matiere ou non-conformite metallurgique. Notre Laboratoire rupture accompagne les industriels de tous secteurs pour analyser des ruptures sur metaux, composites et polymeres, en s’appuyant sur une demarche fractographique et materiaux adaptee au contexte de service. Selon le besoin, l’investigation peut etre rapprochee d’autres expertises en Laboratoire Materiaux afin de relier la rupture aux proprietes de la matiere et aux conditions d’utilisation reelles.

The analysis can highlight several failure mechanisms: brittle fracture, ductile fracture, fatigue fracture, overload, severe impact, excessive deformation, stress corrosion cracking, the presence of inclusions, microstructural heterogeneities, heat treatment defects, grade errors, surface contamination, or an unfavorable interaction with the environment. In the case of polymers and composites, the investigation may also focus on aging, thermal degradation, loss of adhesion, or material embrittlement, with support if needed from polymer analysis by TGA in the laboratory.

The technical means are selected according to the nature of the part and the suspected mechanism. Surface observation can be carried out with a stereomicroscope and then with SEM-EDX to examine the fracture morphology and locally identify chemical elements. Verification of non-conformity can rely on Vickers, Brinell or Rockwell hardness tests, metallographic examination under an optical microscope, as well as composition analysis by ICP or elemental analysis. These tools are particularly useful for metal parts, coatings, and assemblies subjected to high stress.

A visual inspection alone does not always make it possible to reliably identify the fracture initiation point, the propagation sequence, or the underlying causes of the failure. A specialized laboratory provides observations at different scales, objective measurements, and comparisons with sound areas or technical specifications. This approach is essential to qualify a non-conformity, guide corrective action, document an adversarial expert assessment, or validate a material choice.

The laboratory’s expertise is based on observing the fracture surface, comparing it with sound areas or unbroken parts, and characterizing the composition, microstructure, hardness, and any contamination present. analysis may involve SEM-EDX, a stereomicroscope, optical microscopy, Vickers, Brinell or Rockwell hardness tests, as well as chemical analysis by ICP, GC-MS, LC-QTOF, XPS, or other surface techniques depending on the nature of the damage. This approach makes it possible to locate the initiation point, track propagation, qualify the failure mode, and identify aggravating factors related to the environment, coating, or surface condition. To go further in certain cases, the study can be supplemented by a SEM analysis or by expertise in surface analysis of composite materials.

Fractographic observation makes it possible to reconstruct the fracture scenario from the clues present on the surface: fatigue striations, propagation zones, localized initiation, ductile rupture dimples, brittle cleavage, corrosion products, pull-outs, rubbing, or exogenous deposits. Cross-referencing with the surface condition, roughness, adhesion, hardness, and microstructure makes it possible to distinguish a primary cause from a contributing factor.

When the environment is involved, the laboratory can look for oxidizing agents, corrosive substances, or contaminants at the fracture zone or in leachates, using ICP, GC-MS, LC-QTOF, or XPS depending on the matrix and the compounds expected. In the event of a surface defect or adhesion problem, topographical, roughness, surface treatment, and surface contamination examinations may be carried out. This investigation logic also applies to composites and polymers, in connection with the expertise of the Materials Laboratory.

The value of a breakage assessment in the laboratory is also to reduce uncertainty before returning equipment to service, redesigning, changing supplier, or reviewing a process. The analysis makes it possible to determine the likely responsibility of the material, surface condition, treatment, environment, or use. For the manufacturer, this means faster decisions that are better supported and technically defensible.

It is recommended to preserve the broken part and its fragments, document the service conditions, manufacturing history, stresses endured, and operating environment, then send these elements to the laboratory with a reference part if available. This preparation makes it easier to identify the root cause of an industrial failure and speeds up the formulation of corrective actions. The laboratory can then support the manufacturer in analyzing, comparing, characterizing, confirming hypotheses, and guiding the next technical steps.