Heat affected zones in titanium. Metallography failure

[Hector Heras]

Hi:

I am starting a new project, this project is related to machining parts in lathes.
I have experience on grinding process, but very new in turning process.

I did machine a titanium alloy disk (Low pressure disk for turbine) in a puma lathe, when we did the metallography we found heat affected zones.

Here are the main process parameters:
SFM=200
Feed rate = .006
Depth of cut = .010
Coolant = Water base cymtech 310 (concentration = 10)
Lathe = PUMA 400.

Could you please give me an advice on this? Do you have a book that would help me to understand the process parameters interaction? I found some issues with the coolant flow that I already corrected, but prior to machine another part and send it to the lab for analysis, I would like to check the process parameters provided by the programmer.

For example:

In grinding process, there is a theoretical ratio to avoid burn the material or cause thermal damage, qs = sfm / feed rate, qs < 120 in recip and qs>1000 in creep.