Assessment of the stress-oriented precipitation hardening designed by interior residual stress during ageing in IN718 superalloy

The following study presents a novel approach that utilizes residual stresses inside a component to produce stress-oriented precipitation and achieves texture strengthening during the ageing treatment. Refined investigations for the stress-oriented precipitation of γ″ were achieved via transmission electron microscopes (TEM) and neutron diffraction (ND). The results showed that all three variants of γ″ nucleated at short ageing times. The orienting effect of stress was appreciable only during the Ostwald ripening, due to the change of the γ″/γ lattice mismatch. The effect that the stress-oriented precipitation had on the mechanical properties was evaluated and analyzed via tensile tests.