Mechanical Properties and Microstructural Evolution of ODS Alloys Utilizing Solid State Welds
Dr. Darryl Butt and Dr. Megan Frary
This study evaluates the mechanical properties and microstructural evolution of joining a ferritic alloy (HT-9) to two oxide dispersion strengthened (ODS) alloys: a ferritic alloy (MA956) and a nickel-based superalloy (MA754). The joints were created using two solid-state welding techniques; including, friction stir welding (FSW) and pressure resistance welding (PRW). ODS alloys have been shown to provide exceptional elevated temperature properties and radiation damage resistance due to the finely dispersed oxides. These oxides, usually on the scale of a few nanometers, pin dislocations and thus improve the alloys’ high temperature strength. Possible applications of ODS alloys include nuclear cladding materials for fuel pellet encapsulation and jet engine turbines. The mechanical strength of the welds and the microstructural evolution caused by welding will be compared using crack growth experiments and electron backscatter diffraction (EBSD) about the weld zone.