Proceedings of the XMO Industrial Seminar 2026: Excellence in Manufacturing and Operations
Keywords
High entropy alloys; Surfacing; Twisted-wire direct energy deposition; Cold sintering; CO2 laser sintering
Tracks
CONVERGENT MANUFACTURING
DOI
10.5703/1288284318671
Abstract
High-temperature thermal barrier systems require a graded architecture that transitions from a metallic substrate to a ceramic top coat to mitigate damage caused by mismatches in coefficients of thermal expansion (CTE). This study presents a convergent manufacturing strategy that integrates twisted wire gas tungsten arc (GTA) surfacing with cold sintering (CS), followed by CO₂ laser sintering, to fabricate a robust thermal barrier. High entropy alloy (HEA) bond coats with Al-Cr-Fe-Ni-based compositions were deposited onto Inconel 625 substrates using semi-automatically twisted commercial welding wires (Inconel 625, SS308Lsi, and Al ER4043) via GTA surfacing, resulting in HEA layers predominantly composed of >60 vol% B2 (BCC) phase, with NiAl and FeAl intermetallics varying by composition. A ceramic-rich functionally graded cermet was subsequently fabricated, consisting of a fully ceramic 8 mol% yttria-stabilized zirconia (8YSZ) top layer and underlying YSZ–Inconel graded layers, consolidated via cold sintering at 300°C followed by furnace post-heat treatment. To further enhance surface densification, the ceramic top layer was additionally treated using CO₂ laser sintering. This combined processing route enabled effective densification of the ceramic surface while avoiding conventional plasma spray deposition and prolonged high-temperature ceramic sintering. While the present work focuses on the fabrication and integration of HEA bond coats with a ceramic-rich graded cermet architecture, further optimization of compositionally graded interlayers represents a promising pathway to improve thermal compatibility, interfacial stability, and long-term durability under thermal cycling.
Convergent Manufacturing of Metal-Ceramic Architectures for High-Temperature Environments
High-temperature thermal barrier systems require a graded architecture that transitions from a metallic substrate to a ceramic top coat to mitigate damage caused by mismatches in coefficients of thermal expansion (CTE). This study presents a convergent manufacturing strategy that integrates twisted wire gas tungsten arc (GTA) surfacing with cold sintering (CS), followed by CO₂ laser sintering, to fabricate a robust thermal barrier. High entropy alloy (HEA) bond coats with Al-Cr-Fe-Ni-based compositions were deposited onto Inconel 625 substrates using semi-automatically twisted commercial welding wires (Inconel 625, SS308Lsi, and Al ER4043) via GTA surfacing, resulting in HEA layers predominantly composed of >60 vol% B2 (BCC) phase, with NiAl and FeAl intermetallics varying by composition. A ceramic-rich functionally graded cermet was subsequently fabricated, consisting of a fully ceramic 8 mol% yttria-stabilized zirconia (8YSZ) top layer and underlying YSZ–Inconel graded layers, consolidated via cold sintering at 300°C followed by furnace post-heat treatment. To further enhance surface densification, the ceramic top layer was additionally treated using CO₂ laser sintering. This combined processing route enabled effective densification of the ceramic surface while avoiding conventional plasma spray deposition and prolonged high-temperature ceramic sintering. While the present work focuses on the fabrication and integration of HEA bond coats with a ceramic-rich graded cermet architecture, further optimization of compositionally graded interlayers represents a promising pathway to improve thermal compatibility, interfacial stability, and long-term durability under thermal cycling.