Ni base single crystal alloys with recrystallization cracking prevention coatings

摘要

The present invention relates to a Ni base single crystal alloy having a recrystallization prevention preventing coating capable of preventing grain boundary cracking caused by recrystallization. Ni base alloys containing at least one or more of the grain boundary strengthening elements of the group consisting of Zr, HF, B and C on the surface of the Ni base single crystal alloy containing no grain boundary reinforcing element or with a small added amount, and the heat treatment at the temperature where the Ni base single crystal alloy does not recrystallize A Ni base single crystal alloy having a recrystallization preventing coating which diffuses grain boundary strengthening elements only on the surface of the Ni base single crystal alloy.