Deformation and Damage Mechanisms of High Temperature Alloys: Effects of Component Manufacture on Microstructure & Properties
Sponsored by: TMS Structural Materials Division, TMS: High Temperature Alloys Committee
Program Organizers: Mark Hardy, Rolls-Royce Plc; Jonathan Cormier, ENSMA - Institut Pprime - UPR CNRS 3346; Jeremy Rame, Naarea; Akane Suzuki, GE Aerospace Research; Jean-Charles Stinville, University of California, Santa Barbara; Paraskevas Kontis, Norwegian University of Science and Technology; Andrew Wessman, University of Arizona
Monday 2:00 PM
February 28, 2022
Room: 304B
Location: Anaheim Convention Center
Session Chair: Andrew Wessman, University of Arizona; Jeremy Rame, Safran Aircraft Engines
2:00 PM Invited
Welding and Weldability of Ni- and Ni-Fe-based Superalloys: Joel Andersson1; 1University West
Superalloys are materials with unique characteristics, not at least with regard to their superb temperature capability and strength in relation to ordinary materials such as stainless steel. The superalloys are readily used in aero-engines and specifically the hot section which serves as the most challenging application. It is therefore of high importance that the welds used in the design are of suitable quality to account for the demanding environment. Despite these challenges, fabrication in which welding is commonly utilized is being more and more employed to tailor structural fabrications in an improved manner to reduce weight as well as to increase performance. Two new superalloys, G27 and VDM780, have been developed with matching and improved properties to the well-known Alloy 718 and Waspaloy. This presentation will provide advice and information on welding and weldability aspects of Ni- and Ni-Fe-based superalloys in general and G27 as well as VDM780 in specific.
2:30 PM
Creep Behavior and Durability of Laser Metal Deposited Waspaloy: Romain Bordas1; Roland Fortunier2; Patrick Villechaise1; Jonathan Cormier1; Azdine Nait-Ali1; Sébastien Rix3; Lucie Rat3; 1ENSMA - Institut Pprime - UPR CNRS 3346; 2LTDS, école centrale Lyon, on secondment to ENSMA; 3Safran Aircraft Engines
Creep tests have been performed using LMD-p processed Waspaloy. Different loadings were applied at 700 °C and 850 °C and along different directions. A significant morphological and cristallographic texture was identified as well as porosity. For each condition, a better creep life, a higher ductility and a longer tertiary creep were obtained along lasing direction compared to building direction. Despite similar primary and secondary creep stages, early onset of tertiary creep was systematically observed during creep along building direction. Interrupted tests were conducted to analyze damage mechanisms. Damage starts along specific grain boundaries and is controlled by the morphological texture. High pores density zones and large pores do not control cracks initiation but may contribute to crack (micro-)propagation.
2:50 PM
Defect Control and Mechanical Properties of Laser Powder Bed Fusion Built Haynes 230 for High Temperature Application
: Ziheng Wu1; Junwon Seo1; Nicholas Lamprinakos1; Srujana Rao Yarasi1; Anthony Rollett1; 1Carnegie Mellon University
Nickel-based superalloys are widely applied in high-temperature applications, e.g., heat exchangers, because of their excellent high-temperature mechanical performance. As of today, Haynes 230 is not a standard alloy used in metal additive manufacturing (AM) primarily due to the potential for solidification cracking at fast cooling. Being able to additively fabricate components in Haynes 230 attracts many applications that require the additional advantages leveraged by adopting AM, e.g., higher design complexity. In this study, we successfully fabricated crack-free Haynes 230 parts in a laser powder bed fusion process through process parameter optimization. Tensile, creep, and fatigue tests were performed to show AM and wrought Haynes 230 have comparable mechanical properties. The microstructure was characterized to show how process parameters and heat treatments affect the severity of cracking and mechanical properties.
3:10 PM
Rejuvenation Treatment for Ni-based Single Crystal Superalloys with Process Induced Pre-deformation: Satoshi Utada1; Jeremy Rame2; Patrick Villechaise3; Jonathan Cormier3; 1Department of Materials, University of Oxford; 2Safran Aircraft Engines; 3ENSMA - Institut Pprime - UPR CNRS 3346
During the manufacturing process of Ni-based single crystal superalloy components, unexpected plastic deformation can occur. Plastic pre-deformation between solution and aging heat treatments can be detrimental to the material’s creep and fatigue lives at temperatures above 950 °C, which has been observed in the previous studies. In this study, different types of pre-deformation were introduced to a Ni-based single crystal superalloy and material’s creep life has been evaluated. Rejuvenation treatment method was applied to restore the microstructure and the mechanical properties of different pre-deformed materials. Conditions for successful rejuvenation treatment will be presented for different Ni-based single crystal superalloys, AM1 and CMSX-4 Plus.
3:30 PM Break
3:50 PM
Improving the Creep Properties of High-strength Superalloys Produced by Laser Powder Bed Fusion: Marcus Lam1; 1Monash University
Laser Powder Bed Fusion (LPBF) often produces superalloys with inferior creep properties, limiting the high-temperature load-bearing capability and offsetting some of the benefits of additive manufacturing. One of the critical issues is the inferior microstructure produced after heat treatment. The as-LPBF microstructure often has unique segregation, phase precipitation, defects and grain structures, resulting in undesirable microstructure responses from the conventional heat-treating process. This session presents our studies on modifying the microstructure of a gamma prime bearing superalloy by LPBF to improve its creep resistance. The detailed evolution of grain size, grain texture and gamma prime phases from various heat treatment steps will be revealed and discussed. Creep tests followed by fractography and post-tested microstructure analyses will also demonstrate the creep improvement and the underlying mechanisms. The findings from this research can provide the knowledge in improving the creep property of LFBF-produced superalloys, facilitating their broader applications in high-temperature components.