Material failure analysis and fault-finding techniques

Material Failure Analysis

Material failure analysis is a systematic investigation to identify why a material or component has failed or is not performing as expected.
It includes the study of the material’s physical properties, chemical composition and structural characteristics before and after failure.
Analysis of failures assists in learning about the material behaviour and modifications needed in design, selection, processing, and use of materials.
Significant mechanisms of material failure include corrosion, wear and tear, fatigue, creep and embrittlement.
Fractography is an important part of failure analysis, involving a detailed study of the characteristics of a fracture surface.
Techniques such as microscopy and spectrometry can help to determine whether a failure was sudden (brittle) or gradual (ductile), and whether it was due to a surface defect or internal microstructure.

Visual Inspection is the most fundamental technique, often used as a first step to identify obvious problems like visible cracks, discoloration, erosions or deformations.
Microscopy can be used for a more detailed examination to reveal microscopic details such as grain structure, inclusions, and tiny defects.
Non-Destructive Testing (NDT) methods include radiography, ultrasonics, magnetic particle testing, dye penetrant inspection, and eddy current testing. These methods allow the examination of materials without causing any damage.
Destructive Testing methods include tensile testing, hardness testing, and impact testing. These tests cause permanent deformation or destruction of the sample, but give valuable detailed information about material properties.
Devices such as spectrometers and X-ray diffraction machines can analyse the chemical composition of a material. These techniques are particularly useful in identifying the cause of failures related to corrosion or embrittlement.
Computer simulations can sometimes help understand the circumstances and mechanisms of failure, especially in complex systems where many factors come into play.
Thermographic inspection utilises infrared technology to visualise and analyse thermal energy emitted from an object. This can help identify defects within the internal structure of the material.

Comprehensive documentation and traceability of material and inspection data is crucial in failure analysis.
Detailed records of manufacturing processes, changes made and prior functioning of the material/component should be maintained.
Any modifications, repairs or replacements after commissioning the equipment must also be documented. This will aid in comparing normal functioning condition with the current defective state.
Photographs, sample fragments, inspection records and all data collected during the analysis should be systematically arranged and preserved as these might be required for future reference or deeper investigations.
Correctly documenting all the analysis procedures, observations and conclusions is critical to propose rectifications, improve materials and prevent similar failures in the future. It also helps in potential litigations related to the material/component failure.