Titanium Alloy Dimensional Stability
Titanium Alloy Dimensional Stability
(OP)
I'm looking to choose a Ti alloy for a reference structure for a physics experiment.
The structure is about 15"x6"x6" and is relatively heavily gutted by machining.
The reference surfaces should not move more than 0.5um during 1 year.
Temperature will be stable.
We will heat treat as much as possible during machining, but I'm wondering if there's a Ti alloy that is particularly good in this respect.
The structure is about 15"x6"x6" and is relatively heavily gutted by machining.
The reference surfaces should not move more than 0.5um during 1 year.
Temperature will be stable.
We will heat treat as much as possible during machining, but I'm wondering if there's a Ti alloy that is particularly good in this respect.





RE: Titanium Alloy Dimensional Stability
nick
RE: Titanium Alloy Dimensional Stability
After fabrication, the piece is measured, and other calibration is performed.
However, material creep in excess of 0.5um will take the instrument out of alignment.
Ti was chosen for other reasons, among them strength-to-weight and non-magnetism.
RE: Titanium Alloy Dimensional Stability
Hmmm.. I think that you are going to have to use the highest strength Ti alloy you can get. Will this be subject to temperature changes? External forces?
nick
RE: Titanium Alloy Dimensional Stability
Forces are light. I'm worried about internal stresses.
We'll be gping through several heat treatment cycles and other tricks.
Since internal stresses are a function of (also) microstructure, choice of alloy can be important.
RE: Titanium Alloy Dimensional Stability
RE: Titanium Alloy Dimensional Stability
(out of curiosity... we're not changing the material to glass right now... machining too complex, too late..)
RE: Titanium Alloy Dimensional Stability
http://www.schott.com/optics_devices/english/products/zerodur/
RE: Titanium Alloy Dimensional Stability
This is an uninformed, uneducated SWAG. I would think that either commercially pure or Alpha Phase Titanium (Ti-5Al-2.5Sn) would be the propper choice. With a single phase alloy one would think that dimentional changes due to slow phase changes (Beta to Alpha) would be minimized or eliminated.
RE: Titanium Alloy Dimensional Stability
RE: Titanium Alloy Dimensional Stability
RE: Titanium Alloy Dimensional Stability
RE: Titanium Alloy Dimensional Stability
RE: Titanium Alloy Dimensional Stability
Your part is a little small, so its resonances will be a bit high, but reachable with the right gear.
BK
RE: Titanium Alloy Dimensional Stability
If we can't hit the main modes, we can always weigh it down.
Thanks.