J. Wayne Jones

Professor Emeritus

jonesjwa@umich.edu

2022 Gerstacker

T: (734) 764-7503

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Focused Research Group (FRG): Fundamental Approaches to Design of New Structural Magnesium Alloys

Collaborators: Tresa M. Pollock, Austin Chang (U. Wisconsin), Sindo Kou (U. Wisconsin)
Sponsor: National Science Foundation
The objective of this program is to investigate fundamental aspects of solidification, phase equilibria and deformation mechanisms in order to establish a strong foundation for the design of future high temperature magnesium systems. To accomplish this, a collaborative program between the University of Michigan, the University of Wisconsin and the Ford Motor Company is being conducted. The overall approach consists of (1) selection of promising systems upon which future alloy development programs are likely to be conducted, (2) establishment of full thermodynamic descriptions of these systems through a combined modeling and experimental effort, (3) evaluation of key aspects of the solidification behavior of these systems under realistic casting conditions and (4) investigation of the mechanisms of high temperature deformation and associated high temperature creep properties. Considering the need for a balance of high temperature strengthening, high volume processing approaches and alloy systems that can be produced at reasonable cost, two quaternary systems have been selected for initial investigations: Mg-Al-Ca-Sr and Mg-Al-Ca-Ce. The initial goal of the experimental program has been to investigate phase equilibria and microsegregation in targeted regions of composition in order to refine the thermodynamic descriptions. As the thermodynamic models develop, they are then be utilized to select compositional domains within the quaternary systems that merit more detailed mechanical property studies. High temperature deformation is investigated through the use of conventional optical, scanning and transmission electron microscopy and well as with high-resolution strain mapping techniques. An experimental casting facility (Ford Motor Company) is being used to conduct experiments in the proposed program. Critical issues that motivate this effort include: (1) identification of the key aspects of cast microstructure that control creep, (2) consideration of how higher order elemental additions can be used to alter solidification paths in a beneficial manner for properties, (3) definition of an approach for improving the stability of intermetallic phases near the grain boundaries and (4) how best to structure an efficient combination of experiments and computation to accelerate alloy design in complex structural alloy systems.
Highlights (Click an image for more information)
  • Microstructure of AXJ530

    Microstructure of a Mg-Al-Ca based die-cast alloy (AXJ530) consisting of Mg solid-solution phase and eutectic structure at grain boundaries. A new intermetallic phase, (Mg, Al) 2Ca, with the C36 structure has been identified in the Mg-Al-Ca ternary system for the first time. The intermetallic compound at grain boundaries has a great contribution to the high-temperature strength of this type of material. (Akane Suzuki, supported by NSF-FRG)

  • Fatigue crack growth in a titanium alloy

    The video shown here is a fatigue crack is growing in Ti-6Al2Sn-4Zr-6Mo, an important aerospace alloy. The crack has initiated from a defect that was machined with a femtosecond laser. The goal of studying these crack growth rates is to develop a predictive capability which could be applied to components in service thus maximizing life and minimizing risk of failure. This work was done by Chris Szczepanski with funding from the Air Force Office of Scientific Research.

  • Permanent Mold Casting of a Magnesium Alloy

    This video demonstrates various stages of permanent mold casting of a magnesium alloy. The castings are used for studying solidification characteristics and high temperature mechanical properties. Magnesium is a promising new material for automobiles due to the weight savings it can provide thus increasing the efficiency of automobiles. These alloys are intended for powertrain components, specifically engine blocks, heads and automatic transmission casings. This work was completed by Nick Saddock under the sponsorship of NSF and Ford Motor Company.