fractografie

Fractografie, or fractography, is the study of fracture surfaces of materials to determine how and why a component failed. It combines surface characterization, microscopy, and metallurgical context to infer the fracture mechanism, origin, and progression. Fractography is a central tool in failure analysis, materials research, and design improvement, helping engineers identify causes and prevent recurrence.

The practice relies on careful specimen handling and preparation. A failed part is collected and inspected visually, then sectioned and prepared for imaging. Surfaces may be polished and etched to reveal microstructural features. The main imaging tools are optical microscopy and scanning electron microscopy (SEM); additional techniques include energy-dispersive X-ray spectroscopy (EDS) for chemical information, and advanced 3D imaging methods or focused ion beam (FIB) milling for detailed analysis. Observations focus on features such as surface roughness, dimples indicative of ductile fracture, cleavage facets for brittle fracture, river patterns, striations, beach marks for fatigue, and signs of corrosion or inclusions.

Common fracture modes include: ductile fracture with dimples and a cup-and-cone appearance, brittle fracture with flat, faceted surfaces, fatigue fracture showing initiation zones and propagation with striations or beach marks, and intergranular or transgranular fractures along grain boundaries or through grains. Environmental effects, surface conditions, residual stresses, and manufacturing defects are considered alongside the fracture surface.

Applications span aerospace, automotive, energy, and construction sectors, where fractography supports root-cause analysis, failure prevention, quality control, and material/process optimization. Standards and guidelines from ASTM, ISO, and other bodies provide structured approaches to fracture-surface evaluation and reporting.