High Entropy Alloys IX: Alloy Development and Properties: Alloy Development and Application III
Sponsored by: TMS Functional Materials Division, TMS Structural Materials Division, TMS: Alloy Phases Committee, TMS: Mechanical Behavior of Materials Committee
Program Organizers: Peter Liaw, University of Tennessee; Michael Gao, National Energy Technology Laboratory; E-Wen Huang, National Chiao Tung University; Srivatsan Tirumalai; Xie Xie, FCA US LLC; Gongyao Wang, Globus Medical
Tuesday 2:00 PM
March 16, 2021
Room: RM 10
Location: TMS2021 Virtual
Session Chair: Wen Chen, University of Massachusetts Amherst; Duck Kim, Tennessee Technological University
2:00 PM Invited
High-Entropy Alloys Containing Cu: Effects on Microstructure and Liquid Phase: Reza Abbaschian1; Nicholas Derimow2; Raquel Jaime1; Bryan Le1; 1University of California, Riverside; 2National Institute of Standards and Technology
There has been much progress in the field of high-entropy alloys (HEAs) over the past 17 years. However, there is still uncertainty regarding processing-structure relationships in HEAs, particularly those with Cu. We present on experiments focusing on 3d transition metal HEAs containing Cu and the effects on liquid phase behavior and solidified microstructures. It is observed that depending on alloy combination, Cu can lead to liquid phase separation into Cu-rich and Cu-poor regions, or dendrites surrounded by a relatively soft Cu-rich interdendrites. The alloys with the latter microstructures can be designed such to have dendrites with extremely high hardness surrounded by ductile interdendritic phases, making them suitable for wear applications. For example, CoCrCuTi-X (X=Fe,Mn) contain hexagonal dendritic phases with very high hardness in a Cu-rich interdendritic matrix. These HEAs with Cu will be discussed in order to explore potential applications that could benefit from these multiphase microstructures.
2:25 PM Invited
Accelerated Design of High-entropy Alloys for Gas-Turbine Blade Components: Baldur Steingrimsson1; Joseph Poon2; Michael Widom3; Anand Kulkarni4; Xuesong Fan5; Chanho Lee5; Chuan Zhang6; Michael Kirka7; Jaafar El-Awady8; Peter Liaw5; 1Imagars LLC; Portland State University; 2University of Virginia; 3Carnegie Mellon University; 4Siemens Corporation; 5University of Tennessee; 6CompuTherm LLC; 7Oak Ridge National Laboratory; 8John Hopkins University
The adaptation of high-entropy alloys (HEAs) for stage-one turbine blade applications requires comprehensive understanding and significant optimization for operating in the extreme environment of gas-turbine engines. Currently, stage-one turbine blades cast from nickel-based superalloys have limitations in material properties, capping the combined cycle efficiency (CCE) to ~ 62%. To achieve CCE exceeding 65%, at least a 300oC increase in the combustor-firing temperature is required, putting demanding requirements on existing base alloys. However, the exponentially-large composition space of HEAs poses major challenge, in particular to maintain robust microstructures, high damage tolerance, structural integrity, and environmental resilience at 1,300oC. We present a framework for developing transformative refractory-based HEAs utilizing fundamental data science driven by high-throughput calculations and experimentation. We seek to rapidly identify and develop suitable refractory-based HEAs and necessary material-processing science through utilization of Integrated Computational Materials Engineering (ICME). Several promising HEA candidates with potential strengthening mechanisms are identified for exploration.
2:50 PM Invited
Effect of Process Parameters on the Microstructure and Mechanical Properties of Wire+Arc Additively Manufactured AlCoCrFeNi High Entropy Alloy: Rumman Ahsan1; Xuesong Fan2; Gi-Jeong Seo1; Peter Liaw2; Duck Bong Kim1; 1Tennessee Technological University; 2The University of Tennessee, Knoxville
Gas tungsten arc (GTA) - Wire + arc additive manufacturing (WAAM) is characterized by the independent control of the arc and the consumable. This makes it suitable for additive manufacturing with any metallic materials, including the high entropy alloys (HEAs). In this work, the GTA-WAAM with a pre-alloyed and extruded AlCoCrFeNi HEA has been explored. Initially, single layers of HEA are deposited with a range of process parameters. Through in-situ process monitoring (current and voltage), high-dynamic-range imaging, bead cross-section measurement, and statistical analysis; energy density (> 80 W/mm3 is required) have been identified as the primary factor controlling the bead geometry and continuity. Using the same energy density, multi-layer thin-walled structures are deposited with two different heat inputs (310 and 930 J/mm). The microstructure, tensile strength, and failure locations have been investigated. GTA-WAAMed HEA has been found to exhibit comparable mechanical performance with casted- and hot-isostatic-pressed AlCoCrFeNi HEA.
3:15 PM Invited
Welding Metallurgy and Weld Properties of High Entropy Alloys: Carolin Fink1; Alexander C. Martin1; 1Ohio State University
The ability to be joined and formed into complex shaped components is an important constraint for structural use of high entropy alloys (HEA). Welding is a critical fabrication process that is challenging due to its non-isothermal nature and complex chemical and physical reactions. Weld microstructures and properties directly affect service performance of welded components. Hence, a detailed understanding of the metallurgical and mechanical response in HEA considering both fusion based and solid-state welding processes is increasingly important to expand their future range of application. This talk highlights current research on weld microstructure evolution and weld structure-property relationships for main HEA systems. Results from advanced characterization techniques, physical simulation and thermodynamic and kinetic modeling are reviewed. Challenges such as strength reduction, formation of intermetallic compounds or changes in phase transformation and transformation temperatures are discussed. Finally, opportunities to implement welding consideration in the HEA development process are presented.
3:40 PM Invited
Fabrication of Medium- and High-entropy Alloys Using Electroplating and Radio Frequency Plasma: Yu Zou1; 1University of Toronto
In this first part of this talk, we investigate a series of equiatomic binary NiCo, ternary NiCoFe, NiFeCr, and quaternary NiCoFeCu nanocrystalline alloys, produced using electrodeposition. The alloys were subsequently processed with heat treatment at temperatures in the range 573-823 K. Nanoindentation were applied to identify the temperature dependency of mechanical properties. Our study demonstrates a scalable method for producing high-strength and thermally stable HEAs. In the second part of the talk, we demonstrate a radio frequency inductively coupled plasma (RF-ICP) fast method for preparing MEAs and HEAs in a fast and a high-throughput fashion, using the radio frequency inductively coupled plasma (RF-ICP) technique. Typical bulk MEAs and HEAs are successfully synthesized within less than 40s per alloy, thereby greatly improving the fabrication efficiency and throughput.
4:05 PM
Friction Stir Gradient Alloying: A Novel High-throughput Screening Technique to Explore HCP to BCC Transformation in a γ-FCC Dominated High Entropy Alloy by V Addition: Priyanka Agrawal1; Shivakant Shukla1; Sanya Gupta1; Priyanshi Agrawal1; Rajiv Mishra1; 1University of North Texas
The compositional possibilities in high entropy alloys (HEAs) are vast; ergo effective strategies are needed for potential alloy chemistries. Friction stir gradient alloying (FSGA), a novel high-throughput solid-state screening technique is developed to create a library of composition and microstructure in HEAs. In the present study, FSGA aided the selection of suitable V concentration, ~1 at.%, which enabled the nucleation of α-bcc in a low stacking fault energy transforming high entropy alloy with dominant γ-fcc phase. This is the first observation of ε-hcp to α-bcc transformation in a TRIP-HEA and supports the Olson-Cohen model of martensitic transformation (γ-fcc (111) -> ε -hcp (10-11)-> α-bcc), where ε-hcp is the predecessor for the formation of α-bcc. The present work is the first to study the dual effect of chemistry and strain resulting in the co-existence of all three phases and details the evolution path of the transformation.
4:25 PM
Exploring the Structure-property Relationships of (Ti, TiAl6V4)xCoCrFeMnNi Graded High Entropy Alloy: Michael Melia1; Jonathan Pegues1; Mark Rodriguez1; Raymond Puckett1; Shaun Whetten1; Nicolas Argibay1; Andrew Kustas1; 1Sandia National Laboratories
High entropy alloys are a promising group of materials with seemingly limitless and unexplored composition spaces capable of producing physical/mechanical properties that exceed those of conventional materials. Utilizing an additive manufacturing enabled high throughput materials discovery framework, titanium graded high entropy alloys are screened to establish first order structure-property relationships. Compact metallurgical (Ti, TiAl6V4)xCoCrFeMnNi specimens spanning x = 0 – 100% at. fractions were fabricated using in-situ alloying enabled by powder based directed energy deposition. Microstructure evolution as a function of specific (Ti, TiAl6V4)xCoCrFeMnNi compositions were identified through a combination of XRD/XRF and SEM-EDS/EBSD. Microhardness and corrosion measurements were also performed to rapidly establish baseline structure-property relationships. Functional composition maps identifying compositions that promote solid solutions, multiple phases, intermetallics, high hardness, and brittleness are discussed in relation to the alloy-specific microstructural characteristics and configurational entropy