|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Phase Transformation Across Multiscale Material Interfaces
||Transient-liquid-phase-bonding and Mechanical Properties of Ni-based-superalloy-H230 for Heat Exchangers in Supercritical CO2 Power Cycles
||Monica Kapoor, Omer Dogan, Kyle Rozman, Jeffrey Hawk
|On-Site Speaker (Planned)
Transient-liquid-phase-bonding (TLPB) of Ni-based-superalloy-H230 is investigated for potential utilization in microchannel heat exchangers (µHX). These µHX operate at 700°C-800°C and 20-30 MPa in sCO2 power cycles. The two surfaces to be joined by TLPB are coated with a low-melting interlayer, NiP in this case. The interlayer melts at the bonding temperatures thereby enhancing diffusion processes to aid the formation of a bond across the two surfaces. Ideally, this bond should form a homogeneous microstructure without any second phases in order to have uniform mechanical properties across the structure. The H230 TLP-bonded stacks fractured through the joint region on tensile testing and the plastic strain was constrained in the vicinity of the fracture region. These stacks were creep tested at 800°C and their performance compared to that of bulk H230. Scanning and transmission electron microscopy of creep-tested samples to understand failure mechanisms in the stacks has been performed.
||Planned: Supplemental Proceedings volume