Faculty Directory

Armstrong, Dr. Ronald W.

Armstrong, Dr. Ronald W.

Professor Emeritus of Mechanical Engineering
Mechanical Engineering



  • Postdoctoral Studies, Leeds University, UK, 1959
  • Ph.D., Carnegie Mellon University, 1958
  • B.E.S., Johns Hopkins University, 1955




  • AIME Robert Lansing Hardy Gold Medal for 1962
  • Senior Fulbright‑Hays Fellow, New Zealand, 1974
  • NATO Advanced Study Institute Lecturer, England 1979, Crete 1985
  • Who's Who in America, 1982‑89
  • Liaison Scientist, Office of Naval Research‑London, UK 1982‑1984, 1991
  • Visiting Research Fellow, now Life Member, Clare Hall, Univ. Cambridge, UK, 1984
  • Symposium in Honor of Professor Ronald W. Armstrong, Dynamic Deformation: Constitutive Modeling, Grain Size, and Other Effects, TMS 2003, 132nd Annual Meeting and Exhibition, 3/2-6/2003, San Diego, CA; see Metall. Mater. Trans. A, 35A, 2545-2745 (2004).
  • DYMAT John Rinehart Award, 2015
  • Invited to present/publish more than 50 technical papers in Symposia, among more than 400 technical journal and symposium publications.




  • Fellow - American Society for Metals
  • Life Member - Clare Hall, University of Cambridge, U.K.
  • Honorary Member - Materials Research Society of India and Indian Institute of Metals
  • Member - American Physical Society; American Society for Materials; The (TMS) Minerals, Metals and Materials Society; and, Materials Research Society.


Strength and structure of materials Dislocation modeling, crystallography X‑ray diffraction topography Single crystal/polycrystal deformation/fracturing Explosive crystals Dynamic plasticity Fracture toughness Hardness testing Prosthetic devices Electronic materials

RECENT PUBLICATIONS (among ~400 in journals, books and proceedings)      

  • R.W. Armstrong, W.L. Elban, and S.M. Walley, Elastic, Plastic, Cracking Aspects of the Hardness of Materials. International Journal of Modern Physics B, 27, [8], 1330004 (2013).
  • (invited) R.W. Armstrong, 60 Years of Hall-Petch: Past to Present Nanoscale Connections, Symp. Strength of Fine Grained Materials – 60 years of Hall-Petch, Univ. Tokyo, 7/16-18/2013; (Japan) Materials Trans., 55, [1], 2-12 (2014).
  • (invited) R.W. Armstrong, Bertram Hopkinson’s pioneering work and the dislocation mechanics of high rate deformations and mechanically-induced detonations, Phil. Trans. Roy. Soc. A, 372, 20130181 (2014); DYMAT Hopkinson 1914-2014 Centenary Conference, Cambridge, U.K., 9/9-11/2014 .
  • (invited) R.W. Armstrong, Symmetry aspects of dislocation-effected crystal properties; material strength levels and x-ray topographic imaging, Symmetry, 6, 148-163 (2014).
  • (invited) R.W. Armstrong, Sir Alan Cottrell and the dislocation mechanics of fracturing, Cottrell Memorial Symposium, 13th Int. Conf. Fract. (ICF13), 6/16-21/2013, Beijing, CN; Int. J. Strength, Fracture and Complexity 8, 105-115 (2013/2014).
  • R.W. Armstrong and J.G. Glenn, Electrical Role for Severe Storm Tornadogenesis (and Modification), J. Climatology & Weather Forecasting, 3, [3], 1000139 (2015).
  • (invited) R.W. Armstrong and Q.Z. Li, Dislocation mechanics of high rate deformations, Metall. Mater. Trans. A, 46A, 4438-4452 (2015).
  • V.E. Panin and R.W. Armstrong, Hall-Petch analysis for temperature and strain rate dependent deformation of polycrystalline lead, (RU) Physical Mesomechanics, 18, [3], 5-10 (2015).
  • R.W. Armstrong, Material grain size and crack size influences on cleavage fracturing, in theme issue 'Fracturing across the Multi-scales of Diverse Materials',  edited by R.W. Armstrong, S.D. Antolovich, J.R. Griffiths and J.F. Knott, Phil. Trans. R. Soc. A373, 20140124 (2015).
  • R.W. Armstrong, Crystal Dislocations, Crystals, 6, [1], 9 (2016).
  • (invited) R.W. Armstrong, Dislocation Pile-ups, Material Strength Levels and Thermal ActivationMetall. Mater. Trans. A47A, 5801-5810 (2016).
  • (invited) R.W. Armstrong, Plasticity: Grain Size Effects III, in Materials Science and Materials Engineering (MSME) module, edited by S. Hashmi, Elsevier, Oxford, UK, (2016) pp. 1-23.
  • R.W. Armstrong and N. Balasubramanian, Physically-based and Power Law Constitutive  Relations for Higher Temperature Metal Processing and Creep-type DeformationsJOM, 69, 822-829 (2017). 
  • (invited) R.W. Armstrong, Dislocation Pile-ups, Strength Properties and Fracturing (RU) Rev. Adv. Mater. Sci.48, 1-12 (2017).
  • (invited) R.W. Armstrong, Hall-Petch Relationship in Aluminum and Its Alloys, in Encyclopedia of Aluminum and Its Alloys, edited by G.E. Totten, M. Tiryakioglu and O. Kessler, Taylor and Francis Group, UK, (2018).
  • R.W. Armstrong, S.M. Walley and W.L. Elban, editors: Crystal Indentation Hardness, Ebook: Crystals journal Special Issue, MDPI, Basal, CH, (2018) 323 pp.
  • (invited) R.W. Armstrong, Size effects on material yield strength/deformation/fracturing propertiesJ. Mater. Sci., 34, [13], 2161-2176 (2019).   
  •  (invited) R.W. Armstrong and W.L. Elban, Dislocation Reaction Mechanism for Enhanced Strain Hardening in Crystals Nano-indentationsCrystals10, 9 (2020).
  • (invited) R.W. Armstrong, Takeo Yokobori and Micro- to Macro-fracturing of PolycrystalsStr. Fract. and Complex.12, [2-4], 79-88 (2020).
  • J.P. Hirth and R.W. Armstrong, Straight and curved disclinations and dislocation equivalents, Philos. Mag., 101, [1], 25-37 (2021).
  • (invited) R.W. Armstrong, Dislocation and Grain Size Roles in Physical Mesomechanics, (RU) Phys. Mesomech.24, [4], 418-425 (2021), In memoriam of Professor Victor E. Panin
  • R.W. Armstrong and W.L. Elban, The micro- and nano-scale dislocation mechanics of (001) MgO crystal hardnessPhilos. Mag. Letts.101, [12], 455-463 (2021).
  • (invited) R.W. Armstrong, Constitutive relations for slip and twinning in high rate deformations: A review and updateJ. Appl. Phys., 130, 245103 (2021).
  • R.W. Armstrong, W.L. Elban and S.M. Walley, Nano-Indentation Hardness and Strain Hardening of Silicon, Sodium Chloride and Tungsten CrystalsExp. Mech.62, [2], 359-364 (2022). 
  • R.W. Armstrong, High-Rate Crystal/Polycrystal Dislocation Dynamics, Crystals, 12, 705 (2022).
  • (Editorial) R.W. Armstrong, The Dislocation Mechanics of Crystal/Polycrystal PlasticityCrystals, 12, 1199 (2022); in Crystals journal Special Issue: Dislocation Mechanics of Crystal/Polycrystal Mechanical Strength Properties, open: July 2022 - February 2023. 
  • (Editorial) R.W. Armstrong, Metal Crystal/Polycrystal Plasticity and StrengthsMetals12, 2070 (2022); in Metals journal Special Issue: Metal Crystal/Polycrystal Plastic Strain Hardening, co-edited with J.D. Clayton, open: November 2022 - September 2023.  

Armstrong Receives 2015 John Rinehart Award

Mechanical Engineering Professor Emeritus Ronald Armstrong receives 2015 John Rinehart Award work in dynamic deformation.

Armstrong Co-Edits New Royal Society Philosophical Transactions Themed Journal

The Royal Society publishes "Fracturing across the Multi-scales of Diverse Materials."

Armstrong Delivers Keynote at International Symposium in Tokyo

Professor Emeritus Ronald W. Armstrong gives keynote speech at international symposium.

Other professional society fellows

  • American Society of Metals