I am not equipped to answer the physics and metallurgy parts of this question, but I can provide insight into temperature ranges. From a proprietary aerospace prime spec:
"When it is necessary to heat parts after peening...the temperatures shall not exceed the following:
Aluminum alloys 250F
Titanium alloys 475F
Nickel Alloys 1000F
Carburized Steels 275F
52100 Steel 285F
All Other Alloy Steels 475F"
