One Man’s Trash

There’s beauty in failure - in life and especially in metallography. When the wind is at your back and seas are calm, your “brain-muscles” are atrophying. Failure forces us to adapt, to change our mindset. Failure challenges us in a way that success never could.

What you see above, is a failed sample. Thing’s didn’t work out for mr. metal up there. It was pretty clear that this sample was “off” even before it was even sectioned. It had significant cracking and macroporosity. Polishing revealed regions of dissimilar metal.

We could have trashed this sample right there, but I proceeded anyway. See, without even putting this sample under a microscope my team knew that the information we hoped to gather from microscopy would be heavily asterisk’d by being a severely inhomogeneous sample/microstructure. It was a dud, and probably not worth much analysis time.

Not all was lost, however. This sample had sister samples being prepared alongside it. This was a new material system for me, so I knew I was going to need extra samples to dial in etching procedures. I etched 4 of the sister samples, and did not have good results, but succeeded in destroying the microstructures. I was down to my last attempt before having to re-polish (time consuming and frustrating).

What you see above is a result of a hail Mary on a “dud” of a sample. Bulk and local inhomogeneity give rise to wildly different etching rates. Differing etching rates of microstructural constituents is a mechanism that drives contrast in microstructures. Inhomogeneity often yields beautiful gradients that roughly follow chemical gradients across the specimen.

A metallurgist’s trash is often a metallographer’s treasure. I hope you enjoy these images as much as I do!