Thermal Barrier Coatings on Additively Manufactured superalloy HAYNES®282® substrate: microstructure and lifetime investigation.
2023 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE credits
Student thesis
Abstract [en]
Developing the hot sections of the turbine engine parts using Additive Manufacturing (AM) technology has recently increased. The main aim of using AM technology is its ability to build complex shapes quickly and with fewer steps, reducing the manufactured part cost. In addition to the fact that AM can manufacture lightweight parts compared to the conventional manufacturing method, which makes it attractive to aircraft manufacturing companies. In addition to the enormous challenge of manufacturing the Ni-based superalloy by conventional processes such as machining, finding another manufacturing method that could manufacture complex shape parts, lightweight and cheaper, was essential. That makes the AM a desirable method for developing the hot sections of the turbine engines. Thermal Barrier Coatings (TBCs) have been used to protect conventionally manufactured parts from the high temperature in the gas turbine for several decades. In order to protect the AM component in the hot section of the turbine engines, the TBC still needs to protect these components to enhance the lifetime. The study's goal is to develop a TBC layer sprayed on to HAYNES®282® EBPBF additive manufactured and investigate the functional properties and the microstructure of TBCs deposited on additively manufactured substrates, then compare it with Thermal Barrier Coating on the conventional substrate. The NiCoCrAlY was used as powder feedstock and High-Velocity Air-Fuel (HVAF) process to deposit the bond coat. The Suspension Plasma Spraying (SPS) process was used to deposit the topcoat, and Yttria-Stabilized Zirconia (8YSZ) was used as feedstock with two different suspensions, water and ethanol based, with different parameters as the topcoat layer. The samples with different suspension-based and different substrate manufacturing methods and materials were characterized to measure the porosity, crack density, and coating thicknesses. The substrate, bond coat, topcoat surface roughness for AM, and standard substrate for different suspension-based results obtained, the erosion test of the topcoat obtained, and the relation between the results and the microstructure and substrate surface roughness were explained in addition to the Thermal Cycle Fatigue test (TCF) results and its relation to the microstructure and performance of the TBC with different parameters and suspensions. The results showed that the substrate manufacturing process and material affect the microstructure and the lifetime; the AM H282 substrate showed a lower TCF lifetime compared to the standard H283 regardless of the top coat suspension based, the low crack density of the AM H282 compared to standard H282 could be one of the reasons that lead to the early failure of the H282 AM sample.
Place, publisher, year, edition, pages
2023. , p. 43
Keywords [en]
Thermal Barrier Coating, Suspension Plasma Spraying, Additive Manufacturing, Electron Beam – Powder Bed Fusion, Thermal Cyclic Fatigue.
National Category
Mechanical Engineering
Identifiers
URN: urn:nbn:se:hv:diva-20499Local ID: EXM903OAI: oai:DiVA.org:hv-20499DiVA, id: diva2:1782121
Subject / course
Mechanical engineering
Educational program
Masterprogram i tillverkningsteknik
Supervisors
Examiners
2023-07-182023-07-122023-07-18Bibliographically approved