On the mechanisms of high-temperature intergranular embrittlements of Ni3Al-Zr Alloys
Journal
Metallurgical Transactions A
Journal Volume
23
Journal Issue
4
Pages
1187-1193
Date Issued
1992
Author(s)
Abstract
Recent studies on the room-temperature fracture behavior of Ni3Al-Zr alloys after preexposure at elevated temperatures show various types of intergranular failure. In the presently studied Ni78Al21Zr1B0.2 alloy, a strong intergranular fracture tendency at room temperature has been found after preexposure at 750 °C, which is caused by the grain boundary precipitation in this alloy. After short-term exposure above 1200 °C and bending fracture at room temperature, the alloy also suffers intergranular embrittlement due to grain boundary melting. The intergranular fracture appearance is quite different from that observed in a previous study for a Ni77.4Al22Zr0.6B0.2 alloy after air exposure for 100 hours at 1200 °C. In that case, the intergranular fracture was accompanied by grain boundary diffusion (invasion) and segregation of oxygen. The mechanisms of these types of grain boundary failure are discussed. © 1992 The Minerals, Metals and Materials Society, and ASM International.
Type
journal article