Research Metallurgist,
Confluent Medical Technologies
Postdoctoral Research at Mines: 3D Printing of Biomedical Shape Memory Alloys


Behnam’s research is focused mainly on the development and engineering of new biomedical shape memory alloys for additive manufacturing (3D printing) production. Conventional NiTi shape memory alloys need prior cold work to achieve the proper superelastic behavior. New NiTiHf alloys, by contrast, reach high strength and good superelasticity through the formation of so-called “H-phase” precipitates without initial cold working. These alloys can therefore be good candidates for the 3D printing of shape memory alloys. The first part of Behnam’s project applies different chemical compositions and heat treatments to achieve proper mechanical properties and martensitic transformation temperatures. The microstructure of these alloys is investigated in detail using advanced microscopy techniques, such as scanning electron microscopy (SEM), focused ion beam (FIB), electron backscatter diffraction SEM (EBSD-SEM), high-resolution transmission electron microscopy (TEM), scanning TEM, and STEM-EDX, among others. These fundamental studies can reveal the responsible mechanisms affecting transformation temperature, superelasticity, and plastic deformation in these alloys. The second part of the project focuses on optimizing processing parameters for additive manufacturing of NiTiHf and characterizing 3D-printed parts in detail.

Research funded by Confluent Medical Technologies
Collaborators: Tom Duerig, Confluent Medical Technologies; Ronald Noebe, NASA Glenn Research Center



  1. Gallmeyer, T.G., Moorthy, S., Kappes, B.B., Mills, M.J., Amin-Ahmadi, B., Stebner, A.P. “Knowledge of Process-Structure-Property Relationships to Engineer Better Heat Treatments for Laser Powder Bed Fusion Additive Manufactured Inconel 718,” Additive Manufacturing, in press, 10.1016/j.addma.2019.100977.
  2. M. Marteleur, H. Idrissi, B. Amin-Ahmadi, F. Prima, D. Schryvers, P.J. Jacques, “On the nucleation mechanism of {112} ⟨111 ⟩mechanical twins in as-quenched metastable Ti-12 wt.% Mo alloy,” 2019, Materialia, 7:10041810.1016/j.mtla.2019.100418.
  3. B. Amin-Ahmadi, R.D. Noebe, A.P. Stebner, “Crack Propagation Mechanisms of an Aged Nickel-Titanium-Hafnium Shape Memory Alloy,” Script Materialia, 159:85–88, 10.1016/j.scriptamat.2018.09.019, 2018. 


  1. G. Lumbeeck, H. Idrissi, B. Amin-Ahmadi, A. Favache, R. Delmelle, V. Samaee, J. Proost, T. Pardoen, D. Schryvers, “Effect of Hydriding Induced Defects on the Small-Scale Plasticity Mechanisms in Nanocrystalline Palladium Thin Films,” Journal of Applied Physics, 124:225105, 2018.
  2. A. Shamimi, B. Amin-Ahmadi, A.P. Stebner, T. Duerig, “The Effect of Low Temperature Aging and the Evolution of R-Phase in Ni-Rich NiTi,” Shape Memory and Superelasticity,  10.1007/s40830-018-0193-9, 2018.
  3. C. Du, J.P.M. Hoefnagels, S. Kölling, M.G.D. Geers, J. Sietsma, R. Petrov, V. Bliznuk, P.M. Koenraad, D. Schryvers, B. Amin-Ahmadi, “Martensite crystallography and chemistry in dual phase and fully martensitic steel,” Materials Characterization, 139:411–420, 2018.
  4. B. Amin-Ahmadi, J. Pauza, A. Shamimi, T. W. Duerig, R. D. Noebe, A. P. Stebner, “Coherency strains of H-phase precipitates and their influence on functional properties of nickel-titanium-hafnium shape memory alloys,” Scripta Materialia, 147: 83–87, 2018.
  5. A. Radi, J. Khalil-Allafi, M. R. Etminanfar, S. Pourbabak, D. Schryvers, B. Amin-Ahmadi, “Influence of stress aging process on variants of nano-Ni4Ti3 precipitates and martensitic transformation temperatures in NiTi shape memory alloy,” Materials & Design, 142:93–100, 2018.
  6. B. Amin-Ahmadi, T. Gallmeyer, J. Pauza, T. W. Duerig, R. Noebe, A.P. Stebner, “Effect of a pre-aging treatment on the mechanical behaviors of Ni50.3Ti49.7 − xHfx (x ≤ 9 at.%) shape memory alloys,” Scripta Materialia, 147:11–15, 2018.
  7. H. M. Paranjape, P. P. Paul, B. Amin-Ahmadi, H. Sharma, D. Dale, J.Y. Peter Ko, Y. I. Chumlyakov, L. C. Brinson, A. P. Stebner, “In situ, 3D characterization of the deformation mechanics of a superelastic NiTi shape memory alloy single crystal under multiscale constraint,” Acta Materialia,144:748–757, 2018.


  1. P. P. Paul, H. M. Paranjape, B. Amin-Ahmadi, A. P. Stebner, D. C. Dunand, L. C. Brinson, “Effect of machined feature size relative to the microstructural size on the superelastic performance in polycrystalline NiTi shape memory alloys,” Materials Science and Engineering A, 706:227–235, 2017.
  2. Di Zhang Mu Cao, Ding-Bang Xiong, Zhanqiu Tan, Gang Ji, Behnam Amin-Ahmadi, Qiang Guo, Genlian Fan, Cuiping Guo, Zhiqiang Li, “Aligning graphene in bulk copper: Nacre-inspired nanolaminated architecture coupled with in-situ processing for enhanced mechanical properties and high electrical conductivity,” Carbon,117:65–74, 2017.


  1. X. Yao, B. Amin-Ahmadi, Y. Li, S. Cao, X. Ma, X.-P. Zhang, D. Schryvers, “Optimization of automated crystal orientation mapping in a TEM for Ni4Ti3 precipitation in all-round SMA,” Shape Memory and Superelasticity, 2:286–297, 2016.
  2. T. Pardoen, M. S. Colla, H. Idrissi, B. Amin-Ahmadi, B. Wang, D. Schryvers, U. K. Bhaskar, J.P. Raskin, “A versatile lab-on-chip test platform to characterize elementary deformation mechanisms and electromechanical couplings in nanoscopic objects,” Comptes Rendus Physique, 17:485–495, 2016.
  3. X. Gong, P. Marmy, A. Volodin, B. Amin-Ahmadi, L. Qin, D. Schryvers, S. Gavrilov, E. Stergar, B. Verlinden, M. Wevers, M. Seefeldt, “Multiscale investigation of quasi-brittle fracture characteristics in a 9Cr-1Mo ferritic-martensitic steel embrittled by liquid lead-bismuth under low cycle fatigue,” Corrosion Science, 102:137–152, 2016.
  4. K. Schouteden, B. Amin-Ahmadi, Z. Li, D. Muzychenko, D. Schryvers, C. Van Haesendonck, “Electronically decoupled stacking fault nanocrystals embedded in Au (111) films,” Nature Communications, 14001, 2016.
  5. B. Amin-Ahmadi, D. Connétable, M. Fivel, D. Tanguy, R. Delmelle, S. Turner, L. Malet, S. Godet, T. Pardoen, J. Proost, D. Schryvers, H. Idrissi, “Dislocation/hydrogen interaction mechanisms in hydrided nanocrystalline palladium films,” Acta Materialia, 111:253–261, 2016.


  1. M.S. Colla, B. Amin-Ahmadi, H. Idrissi, L. Malet, S. Godet, J.P. Raskin, D. Schryvers, T. Pardoen, “Dislocation mediated relaxation in nanograined columnar Palladium films revealed by on-chip time-resolved HRTEM testing,” Nature Communications, 6:1–8, 2015.
  2. R. Delmelle, B. Amin-Ahmadi, M. Sinnaeve, H. Idrissi, T. Pardoen, D. Schryvers, J. Proost, “Effect of structural defects on the hydriding kinetics of nanocrystalline Pd thin films,” International Journal of Hydrogen Energy, 40:7335–7347, 2015.
  3. M. Kabiri Samani, X. Z. Ding, N. Khosravian, B. Amin-Ahmadi, Y. Yi, G. Chen, E. Neyts, A. Bogaerts, B. K. Tay, “Thermal conductivity of titanium nitride/titanium aluminum nitride multilayer coatings deposited by lateral rotating cathode arc,” Thin Solid Films, 578:133–138, 2015.


  1. 12. H. Idrissi, A. Kobler, B. Amin-Ahmadi, M. Coulombier, M. Galceran, J-P Raskin, S. Godet, C. Kübel, T.Pardoen, D. Schryvers, “Plasticity mechanisms in ultrafine grained freestanding aluminum thin films revealed by in-situ transmission electron microscopy nanomechanical testing,” Applied Physics Letters, 104:101903, 2014.
  2. H. Idrissi, B. Amin-Ahmadi, B. Wang, D. Schryvers, “Review on TEM analysis of growth twins in nanocrystalline palladium thin films: Toward better understanding of twin-related mechanisms in high stacking fault energy metals,” Physica Status Solidi B, 251:1111, 2014.


  1. B. Amin-Ahmadi, H. Idrissi, R. Delmelle, T. Pardoen, J. Proost, D. Schryvers, “High resolution transmission electron microscopy characterization of fcc – 9R transformation in nanocrystalline palladium films due to hydriding,” Applied Physics Letters, 102:071911, 2013.
  2. B. Amin-Ahmadi, H. Idrissi, M. Galceran, M.S. Colla, J.P. Raskin, T. Pardoen, S. Godet, D. Schryvers, “Effect of deposition rate on the microstructure of electron beam evaporated nanocrystalline palladium thin films,” Thin Solid Films, 539:145, 2013.
  3. J. Peirs, W. Tirry, B. Amin-Ahmadi, F. Coghe, P. Verleysen, L. Rabet, D. Schryvers, J. Degrieck, “Microstructure of adiabatic shear bands in Ti6Al4V,” Materials Characterization, 75: 79–92, 2013.
  4. X. Wang, B. Amin-Ahmadi, D. Schryvers, B. Verlinden, J. Van Humbeeck, “Effect of annealing on the transformation behavior and mechanical properties of two nanostructured Ti-50.8at.%Ni thin wires produced by different methods,” Materials Science Forum, 738:306–310, 2013.


  1. J. Khalil-Allafi, B. Amin-Ahmadi, M. Zare, “Biocompatibility and corrosion behavior of shape memory NiTi alloys in the physiological environments simulated with body fluids for medical applications,” Materials Science and Engineering C, 30:1112–1117, 2012.


  1. J. Khalil-Allafi, B. Amin-Ahmadi, Effect of mold hardness on microstructure and contraction porosity in ductile cast iron,” Journal of Iron and Steel Research International, 18:44–47, 67, 2011.
  2. J. Khalil-Allafi, B. Amin-Ahmadi, “Influence of mold preheating and silicon content on microstructure and casting properties of ductile iron in permanent mold,” Journal of Iron and Steel Research International, 18, 34–39, 2011.


  1. J. Khalil-Allafi, B. Amin-Ahmadi, “Multiple-step martensitic transformations in the Ni51Ti49 single crystal,” Journal of Materials Science, 45:6440–6445, 2010.
  2. B. Amin-Ahmadi, H. Ashuri, “Globular structure of M2 high speed steel by thermo mechanical treatment in the semisolid state,” Journal of Iron and Steel Research International,81:381–386, 2010.
  3. B. Amin-Ahmadi, H. Ashuri, “Semisolid structure for M2 high speed steel prepared by cooling slope,” Journal of Materials Processing and Technology, 210:1632–1635, 2010.


  1. J. Khalil-Allafi, B. Amin-Ahmadi, “The enthalpy and entropy changes of martensitic transformations in NiTi shape memory alloys,” Journal of Alloys and Compounds, 487:363–366, 2009.


Translation of “Shape Memory Materials” (Authors: K. Otsuka and C. M. Wayman) from English into Persian language, J. Khalil-Allafi, A. Mirsepasi and B. Amin-Ahmadi, Sahand University Publications, 2015.

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