Perhaps others will be able to visualize these peculiar phenomena, which show the aluminum-magnesium alloys, in crystallographic terms.
ICE AGE AT AMAG RESEARCH
To discover something new, the AMAG researchers are not afraid of working at -40 ° C
Aluminum gets harder
Already more than 100 years ago, Prof. Alfred Wilm made a groundbreaking discovery in Neubabelsberg near Berlin: Unlike steel, aluminum has the ability to further harden at room temperature. It was suspected very early on that the formation of impurity clusters is crucial in this process. However, with the state of the art at the time, it was impossible to prove. Thus, Prof. Wilm could only record:
Explore where the atoms are sitting
Today, more than 100 years after Wilm's discovery, the level of knowledge about the cold hardening of aluminum is very high. However, clustering is still barely visible. The only direct imaging method available today is by means of an atom probe (see figure above). Here, a sample tip with a size of only 50 nm is prepared to analyze their individual layers.
Men who went into the cold
However, to find out what happens right after the quenching of aluminum, one has to go one step further and prepare the atomic probe tips at more than -30 ° C.
Experience report of the AMAG researchers:
As a team of two - Phillip Dumitraschkewitz (PD) and Prof. Peter Uggowitzer (PU) - we were wrapped in down clothing commensurate with the low temperatures. The preparation work required a great deal of tact. Accordingly, the operator could not wear down mittens. This restriction limited the “length of stay” to approx. 45 minutes each. The fingers were just too cold after that.
Surprisingly, the temperature shock when entering the arctic laboratory was not as great as feared, but our noses dripped constantly and the drip immediately froze into small icicles (see picture below).
The microscope we had brought with us had to be adapted for use in a cold laboratory, because after only a few minutes at -40 ° C, the ball bearings were so tight that nothing could be moved - the table was "frozen", so to speak.
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