Interdisciplinary Communication of Fracture Causes Via a New Three Phase Approach to Fractography

Metallurgists and Materials Engineers form the minority of the engineering profession. It would thus behoove us to explain why things break in a way that is readily comprehensible to the wide range of people interested in our work. This includes mechanical, civil, and electrical engineers, attorneys, quality engineers, even bean counters, who we may have to convince that it's worth spending the extra money on the material or process that will be less likely to "fail." This may readily be achieved by focusing first on how the loading geometry affects the crack orientation, and how the resulting crack orientation is modified by the mechanical behavior of the component. These are features that in many cases are readily visible to anyone with typical human vision. The number of basic choices of loading geometry that is required to convey the basic principles is four, and of the mechanical behavior is two. Combined with a simple explanation of the expected crack location, position, and direction, Materials Engineering focused failure analysts may readily and clearly explain to a wide range of parties whether there is anything "suspicious" about the crack.

By this method it also becomes possible in many, but not all, cases, to create a clear criterion by which one may differentiate benign discontinuities from defects. Furthermore, this method can be used to extract useful information about the fracture even when the crack surfaces are corroded, damaged, or covered with contaminant / deposit. Once all that useful information is extracted from the macro and meso scales, the usual techniques of determining or confirming the damage mechanism with microfractography and materialography may proceed by standard practice.

Using this method is much more conducive to transparency and building consensus than starting off by explaining phase diagrams, fuming etchants, second phase particles and their dislocation interactions.