Failure, and a Career That is Anything But: An LMD Symposium Honoring J. Wayne Jones: Fatigue, Creep, and Other Types of Failure
Sponsored by: TMS Light Metals Division, TMS: Magnesium Committee
Program Organizers: Victoria Miller, University of Florida; Michael Caton, US Air Force Research Laboratory; Nikhilesh Chawla, Purdue University; Trevor Harding, California Polytechnic State University; Paul Krajewski, General Motors Corporation; Tresa Pollock, University of California - Santa Barbara

Tuesday 8:00 AM
March 1, 2022
Room: 209B
Location: Anaheim Convention Center

Session Chair: Benjamin Begley, University of Florida; Paul Krajewski, General Motors Company

8:00 AM  Invited
Understanding Fatigue Damage of Metallic Materials in 4D: Probing Microstructural Evolution in Real-time: Nikhilesh Chawla1; 1Purdue University
    For decades, Prof. Wayne Jones has worked on many areas related to the mechanical behavior of materials. Some of his most important contributions have been in the area of fatigue of lightweight materials. Advances in experimental methods, analytical techniques, and computational approaches, have now enabled the development of in situ techniques that allow us to probe the behavior of materials in real-time. In this talk, I will describe experiments and simulations that address the critical link between microstructure and fatigue behavior of metallic materials, by using a three-dimensional (3D) virtual microstructure obtained by x-ray synchrotron tomography. The approach involves capturing the microstructure by sophisticated in situ testing in an x-ray synchrotron, followed by x-ray tomography and image analysis, and 3D reconstruction of the microstructure. Fundamental damage and crack growth phenomena in aluminum alloys and their composites under cyclic loading and in a corrosive environment will be presented and discussed.

8:30 AM  
Contributions of R. F. Mehl (Carnegie-Mellon University; 1932-76) to Metal Fatigue: K. S. Ravi Chandran1; 1University of Utah
    The contributions of R. F. Mehl to physical metallurgy are well-known. One of his most admired contributions is the formulation of recrystallization theory, which is now known as JMAK (Johnson-Mehl-Avrami-Kolomogorov) theory. The presenter has found some unpublished works of R. F. Mehl in metal fatigue, which seem to reveal his critical thinking and attempts in formulating a quantitative theory for S-N fatigue behavior of metals. Mehl also seemed to have undertaken one of the earliest studies on the statistical aspects of fatigue. He, along with coworkers, also explored the question of reliable determination of endurance stress limit in fatigue. The presenter will highlight Mehl’s contributions to the understanding of metal fatigue and its statistical aspects, which have remained in obscure technical reports. It will also be shown how the physical theory of metal fatigue, recently formulated by the presenter, is also validated by Mehl’s early analyses in this area.

8:50 AM  Invited
Very High Cycle Fatigue (VHCF) Phenomena – Influence of Microstructure on Crack Growth in the Near-threshold Regime Investigated by Means of Ultrasonic Fatigue Testing: Martina Zimmermann1; Tina Kirsten1; Fatih Bülbül2; Marcel Wicke3; Angelika Brückner-Foit4; Hans-Jürgen Christ5; 1Technical University of Dresden; 2Formerly: University of Siegen; 3Formerly: University of Kassel; 4University of Kassel; 5University of Siegen
    It is of common consensus that VHCF behavior is primarily dominated by crack initiation rather than crack growth. However, experimental investigations on long fatigue crack behavior in the near-threshold regime become important whenever defect-afflicted materials are the object of consideration. Moreover, by realizing very low fatigue crack growth rates applying ultrasonic fatigue testing, microstructural characteristics that may act as barrier against fatigue crack propagation can be identified and the nature of a true durability discovered. Ultrasonic fatigue crack growth as was extensively explored at the fatigue laboratory at the University of Michigan (UofM) under the supervision of J. Wayne Jones is the central subject of the contribution. Inspired by his research activities a collaborative research project in Germany on the near-threshold fatigue crack growth behavior in a precipitation-hardened aluminum alloy was initiated, the results will be presented focusing on the barrier effect of primary precipitates and grain boundaries.

9:20 AM Break

9:35 AM  
Tear Resistance of AA7075-T6 Sheet at Room Temperature and 200 °C: Daniel Nikolai1; Eric Taleff1; 1University of Texas Austin
    The tear resistance of AA7075-T6 sheet material was measured at 25 and 200 °C to better understand rupture limited deformation. AA7075-T6 has very limited ductility at room temperature but exhibits increased ductility at 200 °C, for which the stamping of a complex geometry was demonstrated. Tear energies were measured for displacement rates that ranged from 2 mm/min up to 1024 mm/min for tests at 200 °C. Tear propagation energies increased by a factor of ten from 25 to 200 °C. Tear propagation energies at 200 °C decreased exponentially with increasing displacement rate. The direction of tearing influenced tear resistance, with the greater tear resistance along the transverse to the sheet rolling direction. Increased tear resistance at 200 °C is associated with a reduction in flow stress and increased ductility that transitions tearing from shearing fracture at 25 °C to ductile tearing with significant neck development at 200 °C.

9:55 AM  
The Elevated Temperature High Cycle Fatigue Behavior of an Additively Manufactured Al-Ce-Ni-Mn Alloy: Amit Shyam1; Sumit Bahl1; Alex Plotkowski1; Joseph Simpson1; Richard Michi1; Kevin Sisco2; Ryan Dehoff1; Allen Haynes1; Qigui Wang3; 1Oak Ridge National Laboratory; 2University of Tennessee; 3General Motors
    In his long and illustrious career at the University of Michigan, Prof. J Wayne Jones also pioneered the methods for relating the fatigue life of cast aluminum alloys to their porosity distribution. In the present work, application of a similar methodology to predict the 350oC high cycle fatigue life of an additively manufactured Al-Ce-Ni-Mn alloy will be discussed. It will be demonstrated that with well controlled additive processing schemes, the likely crack initiating features including porosity are considerably refined. Impurities such as oxide particles become crack initiation sites and a model incorporating the effect of the size and distribution of these oxides on the fatigue life will be presented. Based on the results, the authors will make a case for the considerable promise of additively manufactured aluminum alloys for elevated temperature applications.

10:15 AM  Invited
Hold Time Low Cycle Fatigue of Ni-base Single-crystal Superalloys: Akane Suzuki1; 1GE Research
    Compressive hold time low cycle fatigue is one of the important damage modes in Ni-based superalloy components in aircraft engines and power generation gas turbines. In this study, the hold-time LCF and crack growth mechanisms in single-crystal superalloys were investigated as functions of temperature, strain range and hold time. It was observed that different crack growth mechanisms become dominant depending on temperature and strain range. Roles of a thermally grown oxide layer and a bond coat were evaluated based on observation and modeling of crack growth behavior.

10:35 AM  Invited
Capturing the Full Range: Tracy Berman1; 1University of Michigan
    When working in the laboratory, it is easy to get caught up in the doing: testing samples, taking micrographs, making graphs. One can get lured into a sense of productivity. By asking, “What did you learn this week?” Wayne Jones reminded students that the point of all of these activities is to learn something. We learned about the materials we were studying, how to put together a presentation, and to take high quality images. In the process, we picked up a lot of life lessons from Wayne as well. Perhaps one of his most valuable lessons is to watch out for confirmation bias. This talk explores the scientific and psychological lessons gained from working with Wayne.

11:05 AM Concluding Comments