Fatigue Crack Growth Behaviour of Conventional and Modified IN 718 Superalloys at 650 °C

Abstract

In the present investigation, the fatigue crack growth behaviour of modified IN 718 superalloy (Ni-0.02 %, C-19.04 %, Cr-19.31 %, Fe-3.04 %, Mo-4.73 %, Nb-1.01 %, Al-1.16 %, Ti-0.0033 %, B, all in wt%) has been compared with conventional IN 718 superalloy (Ni-0.02 %, C-19.0 %, Cr-19.35 %, Fe-3.0 %, Mo-5.10 %, Nb-0.50 %, Al-1.00 %, Ti-0.0033 %, B, all in wt%) at 650 °C. Modified IN 718 superalloy exhibits marginally lower crack growth rate as compared to conventional alloy and was attributed to roughness induced crack closure.