Delta Phase and Its Effects On Notch Sensitivity in 718PlusŪ Alloy

ATI 718Plus® alloy is a new cost-effective alloy which fills the gap in temperature capability between 718 and Waspaloy alloy.  In contrast with other 1300°F (704°C) and above capable superalloys such as Waspaloy and Alloy 720, the 718Plus® alloy has significant niobium and can precipitate delta phase.   Previous work has shown that a lack of delta phase is correlated with notch sensitivity.  Through use of a novel testing geometry the notch sensitivity as a function of delta phase fraction and morphology is examined.  An atlas of notch failure probability as a function of structure is presented.