Metallurgy

In early 2008, I accidentally created a beautiful Aluminum alloy during a routine scrap melt to make ingots for later use. I was able to get a sample analyzed by energy disperse spectroscopy (EDS) and used the results to attempt to recreate the alloy.

The crystalline structure is composed of plates and cavities, leading to an intricate surface and interior macrostructure.

Polished (with a 0.25 micron diamond suspension) samples reveal the complex internal structure.

At the time I stumbled upon this Aluminum alloy, I was working at a materials research and development lab preparing metallurgical samples for optical and electron microscopy. The company was kind enough to let me prepare some of my own samples on their equipment and use their optical microscopes to image the various samples.

Optical images of the natural surface of an ingot of the mystery alloy.

I was also able to get my samples analyzed by EDS at a nearby university research lab. In addition to getting a detailed elemental breakdown of the alloy, I got some fantastic images of the crystalling structure of the mystery alloy.

Electron micrographs of a control (relatively pure Aluminum) sample.

Electron micrographs of the mystery alloy.

Using the results of the EDS analysis, I attempted to recreate the alloy using measure quantities its constituents: Aluminum, Copper, Zinc, and Iron. Because the melting point of Iron is so much higher than those of the other constituents, I attempted to dissolve Iron into the melt solution via the thermite reaction. Below, optical images of the resulting alloy demonstrate similar features to those of the target mystery alloy, though they are not quite as pronounced.

The alloy formulated from the results of the EDS analysis of the mystery alloy.

I would really love to hear from anybody who has come across similar alloys or anything like this. If you've seen alloys with macroscopic crystalline structures of can explain some of the metallurgy behind this, I would love to hear from you at andy (at) andreasbastian (dot) com.