Cracks and Failure Analysis

Timely assessments are needed during production and throughout service to establish whether damage has occurred, If so, the investigator will then need to know where the initiation came through why the fault is there (e.g. a visible casting error or contamination), the size of the crack and the distance from point to point.

Cracks can be identified, and their nature analyzed, through a host of different microscopic techniques including inverted microscopy, stereomicroscopy, metallurgic analysis, digital microscopy and, in some indications, traditional measuring microscopy.

More commonly, cracks and structural damage are identified via non-microscopic methods such as resonant frequency, piezoelectric paint sensors and ultrasound. Microscopic techniques can then be employed to provide further clarity and analysis to the damage.

Inverted microscopes are powerful tools in this area as they provide a high level of precision and are strong and durable enough to withstand the weight of an entire engine shaft or gear box, allowing cracks to be identified in situ. Alternatively, damaged parts can be cut out for remote examination then mounted and analyzed under high resolution magnification using digital microscopy and the software associated with this mode of analysis.

Key terms and techniques include: stereo microscopy, inverted microscopy, digital microscopy, software, metallurgy