Aging and precipitation mechanisms of Mg alloys

This work is part of our participation in the DOE-BES funded Center for PRedictive Integrated Structural Materials Science (PRISMS). 

Current and Past team members


Collaborators include Greg Teichert, Krishna Garikipati, Katsuyo Thorton, & Steve Dewitt (UM) and Anirudh Natarajan & Anton Ven der Ven (UCSB)

Our contribution

Evidence of precipitation shearing by dislocations in an aged Mg-Nd alloy. HAADF STEM images of beta”’ precipitates from an undeformed bulk sample (left) and compressed sample (right). Images were taken along the [0001] direction.

Mg, being a light material, presents great potential as a structural material for transportation applications provided that strength, ductility, fracture, and corrosion behavior can be controlled.  Mg-RE alloys are unique among other Mg alloys because they form precipitates that lie parallel to the prismatic planes of the Mg matrix, which is an ideal orientation to hinder dislocation slip. However, RE elements are expensive and impractical for many commercial applications, motivating the rapid design of alternative alloy compositions with comparable mechanical properties. Yet, the unique behavior of Mg-RE remains a puzzle and further insights might provide design guidance for new alloys. 

The main objectives of Ellen’s thesis were to identify the roles of specific RE elements (Nd and Y) on precipitation and to relate the precipitate microstructure to the alloy strength. Ellen’s work focused on the Mg-Nd, Mg-Y, and Mg-Y-Nd systems that contain the main alloying elements of commercial WE series alloys (Y and Nd). In all three alloy systems, a sequence of metastable phases forms upon aging [1-3, 5, 6]. Precipitate composition, atomic structure, morphology, and spatial distribution are strongly controlled by the elastic strain energy originating from the misfitting coherent precipitates [7,9]. The dominating role that strain energy plays in these alloy systems gives rise to very unique microstructures [9]. The evolution of the hardness and precipitate microstructure with aging revealed that metastable phases are the primary strengthening phases of these alloys, and interact with dislocations by shearing [8].



Through this project, we also support the development of Materials Commons. Some of our data can be accessed:


  1.  Chemistry and morphology of b’ precipitates in an aged Mg-Nd-Y-Zr alloy, E Sitzmann, EA Marquis, Phil. Mag. Letters (2015) 95(1) 7-13 link
  2. The structure of ß” and ß’ in an Aged Mg‐Nd Alloy, ELS Solomon, EA Marquis, Magnesium Technology. 151-154 (2016) link
  3. On the early stages of precipitation in dilute Mg-Nd alloys, AR Natarajan, E Solomon, B. Puchala, EA Marquis, A Van der Ven, Acta Materialia (2016) link
  4. The Materials Commons: A Collaboration Platform and Information Repository for the Global Materials Community, B Puchala, G Tarcea, EA Marquis, M Hedstrom, HV Jagadish, JE Allison, JOM, 1-10 (2016) link
  5. Early precipitate morphologies in Mg-Nd-(Zr) alloys, ELS Solomon, V Araullo-Peters, JE Allison, EA Marquis, Scripta Materialia 128 14-17 (2017) link
  6. Aging behavior of Mg alloys containing Nd and Y, E. Solomon, T. Chan, A Chen, B Uttal-Veroff, E. Marquis, Magnesium Technology. (2017)
  7. Misfit-driven β”’ precipitate composition and morphology in Mg-Nd alloys, S DeWitt, ELS Solomon, AR Natarajan, V Araullo-Peters, S Rudraraju, LK Aagesen, B Puchala, EA Marquis, A Van der Ven, K Thornton, JE Allison. Acta Materialia 136 378-389 (2017) link
  8. Deformation behavior of β’ and β”’ precipitates in Mg-RE alloys, ELS Solomon, EA Marquis, Materials Letters (2018) 216(1) 67-69 link
  9. ELS Solomon, AR Natarajan, A Van der Ven, EA Marquis. In preparation for Acta Materialia.


  1. E. Solomon, E. Marquis “The Structure of β” and β’ in an Aged Mg-Nd Alloy” The Minerals, Metals and Materials Society (TMS) Annual Meeting, Nashville Tennessee, February 15, 2016 (Best Student Paper Award)

  2. E. Solomon, E. Marquis “Aging behavior of Mg alloys containing Nd and Y” The Minerals, Metals and Materials Society (TMS) Annual Meeting, San Diego California, February, 2017

  3. E. Solomon, E. Marquis “Precipitate structures in Mg alloys containing Nd and Y” The Minerals, Metals and Materials Society (TMS) Annual Meeting, San Diego California, February, 2017

U.S. Department of Energy – Basic Energy science program [DE-SC0008637] as part of the Center for PRedictive Integrated Structural Materials Science (PRISMS Center)