Advancing Current and State-of-the-Art Application of Ni- and Co-based Superalloys: Alternate Processes
Sponsored by: TMS Structural Materials Division, TMS: High Temperature Alloys Committee, TMS: Corrosion and Environmental Effects Committee
Program Organizers: Chantal Sudbrack, National Energy Technology Laboratory; Mario Bochiechio, Pratt & Whitney; Kevin Bockenstedt, ATI Specialty Materials; Katerina Christofidou, University of Sheffield; James Coakley, Chromalloy; Martin Detrois, National Energy Technology Laboratory; Laura Dial, Ge Research; Bij-Na Kim; Victoria Miller, University of Florida; Kinga Unocic, Oak Ridge National Laboratory

Monday 8:00 AM
February 24, 2020
Room: 11B
Location: San Diego Convention Ctr

Session Chair: Laura Dial, GE Global Research; Bij-Na Kim, Carpenter Additive / Lancaster University


8:00 AM  Invited
Performance of Gamma Prime Alloys Processed Through Electron Beam Melting: Michael Kirka1; Patxi Fernandez-Zelai1; Donovan Lenord1; Obed Acevedo1; Peeyush Nandwana1; Andres Marquez Rossy1; 1Oak Ridge National Laboratory
    Additive manufacturing offers tremendous advantages to the design of critical gas turbine engine components with the opportunity to increase operational performance of the engines on the component and system levels. However, in the case of Ni-base superalloys, understanding the creep and fatigue mechanisms at temperature are of extreme need, as these are the loading conditions that most clearly simulate service conditions in gas turbine engines. This talk will focus on the deformation mechanisms operating during high temperature creep and fatigue of Ni-base superalloys processed through electron beam melting. Specifically, to be discussed are the high gamma prime forming Ni-base superalloys (e.g. Inconel 738/MarM247) processed through EBM and compared to the cast counterparts. Based on currently available results, these materials have been shown to be superior in fatigue compared to the cast counterparts, however, have shown some variability in performance in creep compared to the cast variants.

8:30 AM  
A Comparison of Creep Properties between Conventionally Cast and Additive Manufactured CMSX-4: David Bürger1; Alireza Parsa1; Markus Ramsperger2; Carolin Körner3; Gunther Eggeler1; 1Ruhr-Universität Bochum; 2GE Additive; 3Friedrich Alexander Universität Erlangen Nürnberg
    Recently, it was shown that selective electron beam melting (SEBM) can be used to manufacture single crystal Ni-base superalloys (SXs). SEBM represents a powder bed additive manufacturing near net-shape processing technology, which is characterized by high solidification rates and high thermal gradients. In the present work, the microstructural and creep properties of SX SEBM and conventionally cast materials are compared. The cast material which was produced in a Bridgman process serves as reference state and was homogenized by a typical multiple step heat treatment to establish a fine γ/γ’-microstructure. The SEBM material was investigated in its as-built state, and after an additional homogenization heat treatment. The evolution of the microstructures of the two materials during processing and heat treatment is compared. Creep test with [001] tensile miniature specimen are performed in two stress / temperature regimes (1050 °C, 160 MPa and 850°C, 600 MPa).

8:50 AM  Invited
Innovation in Ni- and Co-base Superalloys at Carpenter Technology Corporation: Stephane Forsik1; Karl Heck1; Ning Zhou1; 1Carpenter Technology Corporation
    Carpenter Technology Corporation focuses on developing and commercializing novel Ni- and Co-base superalloys for mission-critical applications and exploring new additive manufacturing processes. This presentation reviews three novel high-temperature materials that deliver superior performance and provide end users more design flexibility for increasingly challenging operating conditions:• A novel cost-effective conventional cast-and-wrought γ’-Ni3(Ti,Al)-strengthened Ni-base superalloy with improved forgeability and enhanced tolerance to damage providing a new alternative to existing high-temperature superalloy materials.• A crack-free high γ’-Ni3(Ti,Al) volume fraction Ni-base superalloy for additive manufacturing that enables direct printing of turbine parts with complex internal structures and represents an alternative solution to crack-prone CM 247 LC®.• A family of Co-Ni-base γ’-Co3(Al,W) strengthened superalloys, manufactured through cast-and-wrought processing or additive manufacturing, with improved oxidation and sulfidation resistance and high-temperature strength levels similar to conventional nickel-base superalloys.

9:20 AM  
Microstructure and Mechanical Properties of a CoNi-base Superalloy Fabricated by Electron Beam Melting: Sean Murray1; Kira Pusch1; Andrew Polonsky1; Chris Torbet1; Peeyush Nandwana2; Michael Kirka2; Ryan Dehoff2; Ning Zhou3; Stéphane Forsik3; William Slye3; Tresa Pollock1; 1University of California, Santa Barbara; 2Oak Ridge National Laboratory; 3Carpenter Technology Corporation
    Electron beam melting (EBM) for additive manufacturing offers the possibility of advanced component designs using materials for extreme environments. This process can be thought of as a repetitive micro-welding process, where metallic powders are sintered and joined layer-by-layer under vacuum by an electron beam. Many of the advanced nickel superalloys used in critical areas of the hot section of turbine engines are traditionally considered unweldable due to their tendency to crack upon solidification, which is promoted by their high volume fraction of gamma prime that forms shortly after solidification. Here we present the development of a novel CoNi-base superalloy with high gamma prime volume fraction and inherent oxidation resistance that is amenable to the EBM processing route. Microstructure development in the as-printed and heat-treated conditions will be discussed, as well as the mechanical properties in comparison to other gamma prime containing superalloys currently being considered.

9:40 AM Break

10:00 AM  Invited
Advancing Alternate Processing of Rene 65 with Additive Manufacturing: Kelsey Rainey; Laura Dial1; Andrew Wessman2; 1GE Global Research; 2University of Arizona
    Rene 65 is a gamma prime strengthened nickel superalloy developed by GE Aviation primarily for manufacturing disks for turbine engines using forging processes. Differences in the processing route utilizing DMLM result in very different metallurgical structures relative to wrought material. The DMLM process results in an as-built cellular structure of gamma prime formers, with no discrete gamma prime precipitates. Subsequent heat treatment processes enable these discrete precipitates to form, but in different size distributions than one would observe in the wrought material, even for an identical thermal treatment. Supersolvus heat treating the DMLM material does not cause uncontrolled grain growth as seen in wrought material. Consequently, the microstructure and mechanical properties of the DMLM material differ from wrought material even as chemistry and heat treatment conditions remain unchanged, and this provides an opportunity to optimize the material for the properties desired in a variety of applications suitable for additive manufacturing.

10:30 AM  
Analysis of the APB Energy in an Additive Manufactured Polycrystalline Ni-based Superalloy with High γ' Volume Fraction: Larissa Heep1; Casper Schwalbe2; Christoph Heinze3; Antonin Dlouhy4; Catherine Rae2; Gunther Eggeler1; 1Ruhr-Uni-Bochum; 2Cambridge University; 3Siemens AG; 4The Czech Academy of Sciences
    Dislocation structures in the additive manufactured polycrystalline Ni-base superalloy CM247LC (~65 vol.% γ′) are characterized by TEM. The alloy was solution annealed and aged. In this state, a high density of dislocations forming networks at low angle grain boundaries and γ /γ′ interfaces were observed. A few dislocation segments were found in the γ′ phase. The networks contain two sets of dislocations at right angle to each other. Some networks are observed to run through the ordered γ′ phase where its structure changes. In the γ′ phase the lines of the network do not consist of single dislocations but of dislocation pairs with an antiphase boundary (APB) in between. A g-b analysis revealed that the dislocation segments are of screw character with burgers vectors of type 1/2 <101> in both γ and γ′. Based on this analysis, we could estimate the energy of the APB.

10:50 AM  
Development of a New High Energy X-ray Diffraction NDT for High Pressure Turbine Blades: Alexiane Arnaud1; Clément Remacha1; Edward Romero1; Virginie Jaquet1; Frédéric Jenson1; Henry Proudhon2; 1SAFRAN; 2Centre des Matériaux Mines Paristech
    The geometry of the future high pressure single crystal turbine blade may contain internal walls which confer them an higher thermo-mechanical resistance. These internal walls have to be controlled by an NDT test to ensure the monocrystalline arrangement is maintained troughout the part. This is critical as the presence of internal grains can impede the part performance which may cause irreversible damage. The proposed solution is to develop a new industrial NDT system using high energy Laue transmission diffraction method which represents a technological breakthrough in the current industrial environment. A compact laboratory high energy Laue diffraction system, capable of working with actual parts and fast acquisition have been developed. Experimental diffraction image analysis is performed by an in-house indexing algorithm which takes into account the specificity of a laboratory system and make use of a reliable forward simulation model.

11:10 AM  
Ni-based Superalloy Design Exploration by the High-throughput Hot-isostatic-pressing Micro-synthesis Method: Lei Zhao1; Liang Jiang2; Zaiwang Huang3; Lixia Yang1; Hui Wang1; Haizhou Wang1; 1China Iron & Steel Research Institute Group; 2Yantai University; 3Central South University
    A high-throughput micro-synthesis method is developed to study the Ni-based superalloys based on the powder metallurgy sintering approach. A honeycomb array sleeve is made by additive manufacturing firstly, then filled with powder mixture via combinatorial design, densified by hot-isostatic-pressing (HIP) process, homogenized with high temperature heat treatment, and finally prepared a combinatorial superalloy library with more than 80 various chemical compositions. Centered on a base superalloy, the compositions of Co, Ta and Nb are designed to form 6 superalloy groups. This combinatorial superalloy is characterized by LIBS, micro-XRF, Full-view-metallography, SEM, micro-XRD and micro hardness etc. The effects of chemistry on microstructure and property are studied. This work put forward a new high throughput HIP micro-synthesis approach for accelerating the design and screening of superalloys.