CCS and Power Systems

Crosscutting Research - Plant Optimization Technologies

Joining of Advanced High-Temperature Materials

Performer: PNNL - Pacific Northwest National Laboratory

Project No: FWP-12461

Project Description

This project will initially focus on three main tasks: (1) a parametric study to determine process parameters (i.e., spindle rotational and travel speeds, plunge force, and pin diameter/shoulder geometry) that yield defect-free welds in ODS and superalloy materials, (2) mechanical and creep testing of FSW samples welded under optimized conditions, and (3) oxidation and corrosion of FSW material. As part of the latter two tasks, the research team will also perform tests on an equivalent series of specimens fabricated from the unwelded base material. Tensile testing will be conducted over a range of temperatures, from room temperature to 800 °C, initially under inert gas conditions, and creep testing will be conducted at 650, 725, and 800 °C under inert gas conditions. Comparative microstructural analysis will be conducted on a set of witness specimens, as well as select mechanical test specimens, to identify mechanisms responsible for any potential changes in mechanical behavior. If the welding conditions truly have been optimized, there will be little difference in mechanical behavior between the unwelded base material and the FSW region. PNNL investigators will work with researchers at ORNL to devise the appropriate test conditions for oxidation and corrosion testing. The team will experimentally produce highquality welds at various amounts of heat input during the FSW process (controlled via the various tool parameters or secondary induction heating) and the resulting specimens will undergo subsequent oxidation/corrosion testing to determine whether FSW alters the high-temperature corrosion resistance relative to the base material. Select corrosion specimens will be chosen for subsequent tensile, creep, and fracture testing.

Project Details