John in Oly, WA Posted October 5, 2017 Share Posted October 5, 2017 Just beginning to read about metal glass, or "amorphous metal" and the spinning disk method of cooling was mentioned. Also mentioned was the small size of the metal glass produced due to the extreme cooling requirements. Seems a thickness of over 1mm was considered large. More recently the focus seems to be on alloys that form into an amorphous state with slower cooling rates allowing the size of the material to be much larger - several centimeters in thickness. Quote Link to comment Share on other sites More sharing options...
Latticino Posted October 5, 2017 Share Posted October 5, 2017 Then after annealing and cooling, (it was smooth and shiny at this point) heated it back up to 1225F to slump it over a bowl mold. During that process, parts of the surface of the glass developed striations or more or less parallel cracks/grooves - like if you bent something and instead of the material stretching, it developed a texture of hundreds of very small, shallow cracks along the bend. Weird thing was though, it was the inside of the bend. The outside of the slumping bend came out very smooth and shiny. Can't be sure without seeing it, but my guess is that the slumping glass was hotter on the outside surface than the inner surface. Slumping on the outer skin and a combination of folding and bending on the inner. Just like a bend of any material, the inner curve is tighter and that extra crossection needs somewhere to go. If your mold is extremely smooth you might be able to solve by keeping at the slumping temp longer. However then you run the risk of devit, or cracking on differential cooling . Tough call. What little slumping I did was into molds, not over. Quote Link to comment Share on other sites More sharing options...
John in Oly, WA Posted October 5, 2017 Share Posted October 5, 2017 Thanks Latticino. I'll keep experimenting and see what happens with future projects. The part that had the microcracking texture was black glass - the part that stayed smooth was clear glass. I've read that different colors react differently to the heat, so that might have something to do with it. I'm tempted to think the multiple heats didn't do it any good. Like you said, it can take things out of the glass - like overheating steel. Quote Link to comment Share on other sites More sharing options...
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