Quantification of the detrimental effects of precipitate free zones on the yield strength of a superalloy

Precipitate free zones along grain boundaries reduce the yield strength σy of precipitation hardened polycrystals. This reduction Δσy has been measured as a function of the width w of the zones in the γ′-strengthened superalloy NIMONIC PE16. The maximum values of Δσy/σy and w amount to 22% and to 440 nm, respectively.