Materials Failure Analysis

Failure analysis is of great relevance in materials analysis for the industry today. High importance is given to a complete and systematic documentation of the damage as well as all tests and investigations carried out. The documentation not only serves to identify the cause of the damage, but also as a communication basis for an often interdisciplinary team of professionals. In addition it serves as proof to the customer. In particular, the optical documentation of the damage is elemental. For a deep understanding of the propagation and the cause of the failure, holistic documentation of the damage and also the often neglected periphery is highly important. Further investigation of the damaged components is usually carried out with low-magnification stereo microscopes depending on the component size. Segmentable ring, oblique or point light sources help, for example, to display fracture patterns or surface damages (e.g. cracks, holes, grooves). Even digital or zoom microscopes are increasingly used in the field of damage case studies. An important field is the study of corrosion and mechanically induced errors in electrical connections (e.g. solder joints). 

The majority of fractures in mechanical engineering can be attributed to fatigue fractures. The example shows the characteristic fracture surface of a cycled aluminum component with the start of the crack in the lower image section. Here, the documentation is initially carried out by a zoom microscope and is continued for further analysis in the scanning electron microscope. For the final evaluation of the fracture cause, a micro-section of the fracture origin is often examined with reflective light microscopy.

In Germany alone, corrosion damage and its consequences result in costs of billions of Euros annually. In addition to economic damage, corrosion is a significant security risk especially for safety-relevant components such as gas pipes. The light and scanning electron microscopic analysis of corroded components is an important tool chest to determine the causation of corrosion and to determine how to prevent damage like this in the future. To establish the extent of corrosion-damaged area, the gas pipe is documented using a stereo microscope. The smallest corrosion phenomena, such as pittings or incipient hole formation, can be visualized by scanning electron microscopy. The exact cause and manifestation of the corrosion can then be examined again in a micro-section and with reflective light microscopy. Here clear differences between the different types of corrosion are visible. The example shows the characteristics of pitting corrosion. 

Cracked solder joints of microelectronic components lead directly to the failure of the component and at worst, the failure of entire plants and systems. Failure analysis is therefore an indispensable tool to find the cause of damage and to prevent future failures. The example shows a soldered, microelectronic component where it came to fractures on some solder joints, other joints show no damage. Macroscopic documentation was carried out to detect differences between intact and broken solder joints using a zoom microscope. This already shows clear differences. After this, the fracture surface is investigated in the scanning electron microscope. In secondary electron contrast, different fracture patterns are visible. After a careful materialographic preparation of a broken solder joint, the fracture area can be examined through light microscopy. Only in the micro-section and with light microscopy can it be seen that the crack origin is in the solder. The combination of different microscopic techniques and the results obtained then allow the determination of the cause of the damage.