3.2. Analysis of the residual stress profile
Fig. 4 shows the residual stress distribution with depth of the Al-Li alloy after shot peening, a certain depth of
compressive residual stress is generated in the surface layer. The value of compressive residual stress on surface is
-204.3 MPa. The value of maximum compressive residual stress is -265.5 MPa occurred at 81ȝP from surface.
The depth of compressive residual stress profile is about 245ȝP, and then the stress state turns into tensile stress
below this depth.