Electron microscope image of titanium ground at 120 grit

Mecha

Mecha

Titanium Bladesmith
Knifemaker / Craftsman / Service Provider
Joined
Dec 27, 2013
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10,141
Hey guys, I thought you might think this is interesting.

This is an electron microscope image and chemical analysis of a piece of 6Al4V titanium alloy that was being forged and ground into a blade. It's a little piece of the tip that was cut off. In the image, you can see the straight lines of grinding, which is from a somewhat worn 120 grit belt - this is the bevel section. Above the strakes is a more ragged section, that is the flat, ground harshly with high pressure at 36 grit.

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The blade in question and reason for the chemical analysis is here: https://www.bladeforums.com/threads...bird-airframe-titanium.2066626/#post-23412086

Kinda cool to see! :]
 
Cool. How hard did you get it as it's not your usual choice?
Btw, any recommendation to get some Beta C? I'm switching from Ti64 to Beta to make them look better. :))
 
JoeBusic said:
Cool. How hard did you get it as it's not your usual choice?
Btw, any recommendation to get some Beta C? I'm switching from Ti64 to Beta to make them look better. :))
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Alpha Knife Supply used to carry Beta C. I don't see it on the site at the moment, not sure if they're still stocking it. What sort of look are you going for with your titanium projects?

These blades don't get hardness tested anymore, as it's not a very useful test for determining or predicting the mechanical characteristics of heat-treated titanium alloys, although I used to do it quite a bit years ago. This one didn't have any parallel flats to test anyway. I'd guess it was like HRC 44. Most are in the 50-55 range, but it's determined by the alloying elements, not tuned with heat treatment as can be done with tempering steel to a certain level. Titanium alloys are more like bronze than steel.
 
Mecha said:
What sort of look are you going for with your titanium projects?
Click to expand...
I meant for Beta C to look better after my HT. :)
Mecha said:
These blades don't get hardness tested anymore, as it's not a very useful test for determining or predicting the mechanical characteristics of heat-treated titanium alloys, although I used to do it quite a bit years ago. This one didn't have any parallel flats to test anyway. I'd guess it was like HRC 44. Most are in the 50-55 range, but it's determined by the alloying elements, not tuned with heat treatment as can be done with tempering steel to a certain level. Titanium alloys are more like bronze than steel.
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I get that. But hardness is the easiest obtainable number for differentiation when grain refining. Hardness goes up when grains go down. Ti64 I got to 63HRC mixed phase and 66HRC martensite. Getting similar numbers with Beta C would be interesting. I want to try and test it with some other beta alloys. Betas are hard to find.
 
JoeBusic said:
I meant for Beta C to look better after my HT. :)

I get that. But hardness is the easiest obtainable number for differentiation when grain refining. Hardness goes up when grains go down. Ti64 I got to 63HRC mixed phase and 66HRC martensite. Getting similar numbers with Beta C would be interesting. I want to try and test it with some other beta alloys. Betas are hard to find.
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A true, totally single-phase beta alloy would certainly be hard to find. Even the usual beta-metastable alloys end up only mostly beta phase after solution treatment.

I have some near-beta alloys and other interesting ones you could try!

Otherwise, you could look for some 6.5mm thick armor plates from a Soviet era 6B3TM early model ballistic vest. They are VT23 alloy, a near-beta, complex, rich ti alloy which is really excellent for making blades.
 
Good stuff! I just did some forged and solution treated grade 5. It is so hard to grind I have given up for now.
 
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