Long time lurker, first time poster.

I'm designing a titanium shaft with a female spline in it but need some help on the heat treating and aging process. The spline itself will have a coating, probably DLC or Titanium Nitride but I would like to improve the toughness of the substrate a bit too.

I plan to use Ti-6Al-4v. For this alloy I think the standard is to solution treat @ 955-970 degrees C for 1 hr, water cool and then age at 480-500 degrees C for 4 hours. Does this sound correct?

Does titanium in this condition also need a stress relieving process or do you need to do semi-final machining and then stress relive, then final machine? I have done this with materials like Inconel 718 with good results.

My current process plan is to machine, solution treat, age. No secondary machining or stress relieving. Does this sound correct?

If anyone has practical information of Ti heat treating, aging and manufacturing I would really appreciate it. I can find a lot of papers on the subject but they tend to be so specific that they can be hard to apply.

Thanks for any help!