Fatigue in Materials: Fundamentals, Multiscale Characterizations and Computational Modeling: Multi-mechanical Interactions during Extreme Environment Fatigue Loading
Sponsored by: TMS Structural Materials Division, TMS Materials Processing and Manufacturing Division, TMS: Additive Manufacturing Committee, TMS: Advanced Characterization, Testing, and Simulation Committee, TMS: Computational Materials Science and Engineering Committee, TMS: Integrated Computational Materials Engineering Committee, TMS: Mechanical Behavior of Materials Committee
Program Organizers: Garrett Pataky, Clemson University; Ashley Spear, University of Utah; Antonios Kontsos, Drexel University; Brian Wisner, Ohio University; J.C. Stinville, University of Illinois Urbana-Champaign

Tuesday 8:30 AM
March 16, 2021
Room: RM 34
Location: TMS2021 Virtual

Session Chair: Brian Wisner, Ohio University

8:30 AM
Additively Manufactured Haynes 282 Superalloy Using L-PBF: Heat Treatment Effect on Mechanical Properties at Room and Elevated Temperatures: Seyed Ghiaasiaan¹; Nabeel Ahmad¹; Paul Gradl¹; Samuel Cordner¹; Colton Katsarelis¹; William Tilson¹; Shuai Shao¹; Nima Shasaei¹; ¹Auburn University
    Laser beam powder bed fusion (L-PBF) process is an attractive additive manufacturing (AM) technology that is applicable for various applications and numerous metallic alloys. Haynes 282 is one of the gamma-prime strengthened Nickel based superalloys that is recently getting a lot of attention for AM components. The test specimens for this study were produced by a L-PBF system using an EOS 290 machine. The objectives for this study were to first develop the heat treatment procedures required for optimization of structure-property correlation in the AM L-PBF Haynes 282 superalloy. The microstructural evolution of test specimens during heat treatment processes was comprehensively studied by scanning/transmission electron microscopy (STEM) using Energy Dispersive Spectroscopy (EDS) and Backscattered (BS) detectors. Further, Materials Testing Database for uniaxial tensile and fatigue properties of the AM L-PBF Haynes 282 superalloy is provided at room and elevated temperatures.

8:50 AM
Quantification of Fatigue Crack Growth Rates and Fatigue-creep Load Interaction Effects of Heterogeneous Fiber Networks via Thresholded Strain Fields: Sarah Paluskiewicz¹; Yoon Joo Na¹; Christopher Muhlstein¹; ¹Georgia Institute of Technology
    Paper is a heterogenous, anisotropic fiber network with ubiquitous applications. The interlocking fiber network of paper makes it challenging to precisely quantify crack growth over time or cycles. To overcome this difficulty, we thresholded strain maps generated from non-contact digital image correlation in the region around the crack tip at a consistent value (εyy = 0.05) above the fracture strain (εUTS = 0.035). Then we computed crack growth rates (10^-6 to 10^-2 mm/cycle) from fatigue tests with stress amplitudes (5 to 10.8 MPa) that fell between the notched yield strength and notched tensile strength. By studying the crack profile, we identified that for sufficiently high-cycle fatigue, damage accumulation occurs by fiber fracture. This contracted from inter-fiber damage mechanisms found in tensile, creep, and ratchetting. Finally, we found that by alternating specific loading conditions, crack growth rates decreased.

9:10 AM
Rapid Characterization of Cyclic Response of Small-volume Metal Samples Using Spherical Microindentation Stress-strain: Camilla Johnson¹; Soumya Mohan¹; Reji John²; Adam Pilchak²; Surya Kalidindi¹; ¹Georgia Institute of Technology; ²Air Force Research Laboratory
    The cyclic stress-strain response of a material provides insight into fatigue properties that may limit the performance of fracture-critical rotating components in gas turbine engines. Historically, fatigue is a costly property to assess because of the volume of material required for test coupons and also the time to run each test. Therefore, a critical need exists for the development of novel experimental approaches that can rapidly evaluate the relative changes in cyclic response as a function of alloy chemistry and thermo-mechanical processing history. This becomes especially critical in the materials development efforts, which require systematic exploration of a large materials space. In this work, we present a novel approach using spherical microindentation to deduce stress-strain loops for various titanium alloys. The results show promise for obtaining reliable, high-throughput, quantitative assessments of the cyclic response.

9:30 AM
Fatigue Crack Growth in a Ni-rich NiTiHf High Temperature Shape Memory Alloy under Thermomechanical Loading: Behrouz Haghgouyan¹; Benjamin Young¹; Ibrahim Karaman¹; Dimitris Lagoudas¹; ¹Texas A&M University
    A unified methodology is proposed for crack growth in shape memory alloys (SMAs) under two loading paths: mechanical, i.e. loading under constant temperature, and actuation, i.e. thermal cycling under constant load. The methodology is applied to understand the mechanisms contributing to crack growth in the presence of thermal and mechanical induced phase transformation in a Ni-rich NiTiHf high-temperature SMA. In mechanical crack growth, the material undergoes forward transformation upon loading and reverse transformation upon unloading. In actuation crack growth, the material is subjected to thermal cycling under constant load resulting in forward transformation upon cooling and reverse transformation upon heating. The resistance of the material to crack growth under both loading paths is characterized by measuring the crack growth rates corresponding to the range of the applied driving force. The results are expected to provide key insights into the underlying mechanisms that promote crack growth in SMAs.