Bulk Metallic Glass (OSU MATS321 project)

what is wolf Matala class most metals have a clear crystal structure as we can see in this picture the atoms are very organized and there's a grain boundary as shown here metallic glasses differ and then they do not have a crystal structure they are what's called amorphous and are shown in this picture here metallic glasses tend to be stronger than most metals because they do not have the same crystal structure allowing atoms to come fill in sites in between atoms making them stronger in all directions because they do not have stress concentrations along grain boundaries as shown both metallic glasses are stronger than their crystalline alloy counterparts as well as having lower friction being harder being more corrosion resistant and having a lower melting point so the first step here is to figure out what the composition is that you want I just did a quick google search here found that zirconium 55 aluminum 10 nickel 5 and copper 30 makes a good glass forming bulk metallic glass all these numbers here are atomic percentage so it's we aren't even talking about mass or weight yet then over here we go into Excel and as you can see we have our atomic percentages here we just multiply this by the atomic mass that you find on the periodic table to get our atomic weight here and then we just ratio it down to get our total mass that we're looking for I was looking for a little under 10 grams so I just scaled everything down to get these masses here so the next step here is to weigh out all of our different material is just some copper some random-ass here once we have all of our material weighed out we're gonna throw it into some acetone throw it into this bath here let it run once that's done we're gonna dry the acetone ax throw it in some ethanol do the same thing and after that everything is all cleaned and ready to go the next step here is to come over to our Ark melter and we want to clean it off with this bra so that acetone and then ethanol and what this stuff does is it prevents heterogeneous nucleation so why do we have to worry about it being so clean we were processing bulk metallic glass well impurities will cause heterogeneous nucleation heterogeneous nucleation is when there's an impurity inside of a sample and it kicks off nucleation inside of the sample which is which will start a crystal structure which is exactly what you don't want in a bulk metallic glass without crystal structures this is our pump here and pretty much oxygen is our enemy in this system because anything that creates an oxide will create a crystal lattice and that is what we're trying to avoid so next step is to turn on this super cooler does is the arc melting has really cold water running through it so we can cool the liquid the materials are very quickly so once we get down to a certain pressure here what we're going to want to do we're going to want to close the top here and watch it with some cargo what this does is just get some oxygen out of there so once we've gone through three of those washing processes what we're going to want to do is we're going to want to close this valve here open this one here and you're confused we're gonna start this typical pump here and that's really going to create a vacuum in the chamber and we let that go for about five six minutes so once you turn the turbopump off and back to the tank with argon you're ready to start going so the first step with melting is starting to get this zirconium get er hot and what that does is zirconium really likes to create sarkodie my oxide so when you get it hot all the oxide all the oxygen in there will start to form with it so less of it can go into the material you're trying to melt now we start melting the material increased voltage as we go and it will start to create one big kind of blob here we want to make sure we get every little piece in there and we try one try and make it homogeneous as we can and we can watch it cool and hopefully it cools up very quickly because the quicker it cools the less chance of nucleation there is cooling and the atoms try and arrange themselves and the most energy-efficient way which will occur which will make a crystal lattice occur and with the rapid cooling it will make the atoms freeze in their positions and create a more and more fizz structure which we need for bulk metallic glasses so all we're doing right now is I just wanted to turn this into two separate things so we have a button and then we can cast one into a rod what this button does is it pretty much has like a gate down below where we want to cast this rod here and when the button is pressed the gates open and I want to close it right now so when we heat it up in the tank here it will create a pressure differential between what the casting area and then what's in the name and using that pressure differential that I just created what we're gonna do here is we're gonna cast this half of the button down into the copper hole right there just this is what we got not the best rod you've ever seen before but not terrible you as production capabilities of both metallic glasses improves they will start being used in applications such as surgery sensors and small electronics the future is looking strong for both without a boss

Channel: William Miller

Views: 432

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Id: qvbURu2xGfs

Length: 6min 27sec (387 seconds)

Published: Fri Dec 06 2019