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Mechanical synthesis and mechanical properties of nanomaterials

Materials with very small grain size – nano- and submicrocrystalline – demonstrate attractive mechanical properties and unusual deformation behavior. Our aim is to propose physical mechanisms explaining it, and to develop new materials with enhanced mechanical properties.

In this research work the following investigators are involved: Horst Hahn, Julia Ivanisenko, Askar Kilmametov, Roman Kulagin, Dayan Nugmanov, Jiamin Hu and Sree Harsha Nandam. 

At INT nanostructured materials are produced using various methods: „bottom-up“  like inert gas condensation and layer deposition, and “top-down” approach based on the severe plastic deformation (SPD) for microstructure refinement. In particular, high pressure torsion (HPT) has been recently established at INT as the SPD technique for the synthesis of nanostructured metals and alloys possessing sub-micron or even nanometer-sized grains. For many alloys HPT offers a powerful tool for microstructure design on different hierarchical levels. This includes, in addition to grain size refinement, grain boundary design, texture formation, mechanically driven phase transformation, and the formation of metastable phases. In order to study mechanical properties we use custom built tensile stage specially designed for miniature specimens and equipped with laser extensometer for precise strain measurement. Characterization of the samples microstructure is performed using XRD analysis and a variety of TEM methods in collaboration with Christian Kübel Research Group.

 

 

Figure 1. (a) Schematic diagram explaining the principle of high pressure torsion; (b) Tensile “Engineering stress – Strain” curve of HPT-processed Pd-20%Ag alloy. Grain refinement down to 120 nm, as shown in the dark field TEM image in insert, resulted in the increase of strength for six times as compared with coarse grained state. For details see

 

  • Grain refinement and mechanical properties in ultrafine grained Pd and Pd – Ag alloys produced by HPT 

      L. Kurmanaeva, Yu. Ivanisenko, J. Markmann, C. Kübel, A. Chuvilin, S. Doyle,

      R.Z. Valiev, H.-J. Fecht Mat. Sci. Eng. 2010,A 527:1776–1783.

      DOI: 10.1016/j.msea.2009.11.001

 

Research Projects

1. Scaling up of High Pressure Torsion
2. Mechanical behavior of nanoglasses
3. Mechanically driven phase transformations
4. Mechanical behavior and deformation mechanisms of nanocrystalline metals and alloys
5. Mechanical properties of nanocrystalline carbon steels under static and cyclic load
 

 

 

 

1. Scaling up of High Pressure Torsion

In collaboration with Brigitte Baretzky (INT) we scaled up the HPT method for the processing of advanced nanocrystalline materials in amounts reasonable for industrial applications. The new method is named High Pressure Torsion Extrusion (HPTE). During HPTE, a rod-shape specimen is extruded through sectional containers rotating relative to each other (Fig. 2). The specimen is subjected to shear deformation in the area where the containers meet. One of the main advantages of the HPTE process is that already after a single extrusion pass a high accumulated strain (orders of magnitude lager than for Equal Channel Angular Pressing, Twist Extrusion, Cyclic Extrusion Compression, etc.) can be achieved in the specimen. At present, commercially pure copper and electro-technical Al alloy 6101 were successfully processed using HPTE. As a result uniform UFG microstructure was formed and high mechanical properties were achieved.

Figure 2. Schematic diagram explaining the HPTE process (left) and a photo of the 6101 alloy specimen after HPTE processing (right).

Furthermore, the presence of a strong velocity gradient in the specimen cross-section during HPTE provides the possibility to process hybrid materials or composite parts with helical architecture of functional elements. Simulations predict that such composites can combine high strength and ductility. This approach is being studied now in the frames of a German Research Society (Deutsche Forschungsgemeinschaft, DFG) Project „Hybrid ultrafine grained materials produced by high pressure torsion extrusion” (IV98/8-1, 2017-2020).

  • Device and method for forming components made of metallic materials

V. Fedorov, Yu. Ivanisenko, B. Baretzky, and H. Hahn

European patent EP 2 821 156 B1

  • High Pressure Torsion Extrusion as a new severe plastic deformation process

Yu. Ivanisenko, R. Kulagin, V. Fedorov, A. Mazilkin, T. Scherer, B. Baretzky, and H. Hahn

Mat. Sci. Eng. 2016, A664: 247-256, DOI: 10.1016/j.msea.2016.04.008

2. Mechanical behaviour of nanoglasses

In collaboration with R. Schwaiger Group we analyzed the mechanical performance of Cu50Zr50 metallic nanoglasses. We found that the hardness and Young's modulus increase for the nanoglasses compared to melt-spun ribbons. The curves of both as prepared and annealed nanoglass samples are smooth without any pop-ins (indicating homogeneous deformation), while the load vs displacement curves of the melt-spun ribbon of similar composition show clear pop-ins (serrations), indicating the generation of shear bands (inhomogeneous deformation) (Fig. 3a). The area in the vicinity of the Vickers indents in nanoglass (Fig. 3b) clearly does not show any shear bands around the indent whereas the melt-spun ribbons shows shear bands around the indent. It is proposed that the interfacial regions, which are sources of high free volume act as nucleating sites for the formation of numerous shear transformation zones giving rise to homogeneous deformation in nanoglasses.

Figure 3. Representative nano indentation curves of melt-spun ribbon, as-prepared nanoglass and annealed nanoglass at an indentation strain rate of 0.05 s-1. No pop-ins was observed in the nanoglass samples while they were observed in melt-spun ribbons (indicated by arrows) (a); SEM image of the indent in as-prepared nanoglass.

Details of this work are published in:

  • Cu-Zr nanoglasses: atomic structure, thermal stability and indentation properties

S.H. Nandam, Yu. Ivanisenko, R. Schwaiger, Z. Śniadecki, X. Mu, D. Wang, R. Chellali, T. Boll, A. Kilmametov, T. Bergfeldt, H. Gleiter, and H. Hahn

Acta Materialia 2017, 136:181-189. DOI: 10.1016/j.actamat.2017.07.001

3. Mechanically driven phase transformations

Being applied to alloys, severe plastic deformation often leads to mechanically driven phase transformations like forced mixing in immiscible alloy systems, decomposition of supersaturated solid solutions, dissolution of second phase particles or even amorphization.  In our group we study mechanically driven cementite dissolution in pearlitic steels, mixing in immiscible Cu-Ag or Cu-Nb systems and the formation of high pressure w phase in Ti and Ti alloys. Our aim is to understand the physical mechanisms of these processes.

Details of this work have been published in:

  • Forced chemical mixing of immiscible Ag-Cu heterointerfaces using high-pressure torsion

M. Pouryazdan, D. Schwen, D. Wang, T. Scherer, H. Hahn, R. S. Averback, and P. Bellon 

Phys. Rev. B 2012, 86:144302.DOI: 10.1103/PhysRevB.86.144302 http://www.int.kit.edu/img/intern/icon_external_link.gif

  • Transformations of Cu in supersaturated solid solutions under high-pressure torsion

B.B. Straumal, A.R. Kilmametov, A.A. Mazilkin, L. Kurmanaeva, Y. Ivanisenko, A. Korneva, P. Zięba, and B. Baretzky

Mat. Lett. 2015, 138:255–258.

  • Phase Transformations in Ti–Fe Alloys Induced by High-Pressure Torsion

B.B. Straumal, A.R. Kilmametov, Yu. Ivanisenko, A.S. Gornakova, A.A. Mazilkin, M.J. Kriegel, O.B. Fabrichnaya, B. Baretzky and H. Hahn

Adv. Eng. Mat. 2015, 17:1835–1841. DOI: 10.1002/adem.201500143.

  • Self-organized, size-selection of precipitates during severe plastic deformation of dilute Cu-Nb alloys at low temperatures

J.A. Beach, M. Wang, P. Bellon, S. Dillon, Yu. Ivanisenko, T. Boll, and R.S. Averback

Acta Mater. 2017, 140:217-223. DOI:10.1016/j.actamat.2017.08.041

  • The α→ω and β→ω phase transformations in Ti–Fe alloys under high-pressure torsion

A.R. Kilmametov, Yu. Ivanisenko, A.A. Mazilkin, B.B. Straumal, A.S. Gornakova, O.B. Fabrichnaya, M.J. Kriegel, D. Rafaja, and H. Hahn

Acta Mater. 2017, DOI: 10.1016/j.actamat.2017.10.051

4. Mechanical behavior and deformation mechanisms of nanocrystalline metals and alloys

 Nanocrystalline materials with the mean grain size as small as 10-30 nm demonstrate very peculiar mechanical behavior, for example, strong compression/tension asymmetry, extended elastic-to-plastic transition (extended microplasticity stage), propensity to strain localization, stress-induced grain growth and abnormally high cryogenic strength. This is because grain boundaries are obstacles for dislocation motion, as evidenced by the increase of the yield stress of polycrystals with decreasing grain size embodied in Hall-Petch type equations. Thus, when the grain size of a metal is reduced to extremely small values, dislocation activity becomes less important, and indeed computer simulations and experimental studies indicate that the primary deformation mechanism operating at room temperature and conventional strain rates, dislocation slip, is replaced in the nanocrystalline state by such unusual (under the applied experimental conditions) mechanisms and processes as grain boundary sliding, shear banding and grain boundary migration (grain growth).
 

Figure 4. Stress-strain compression curves of nc Pd-10% Au alloy with a mean grain size of 14 nm, as shown in the histogramm in the insert, at different temperatures. For comparison, deformation curves of coarse grained alloy are also shown.  Nanocrystalline samples demonstrate extended microplastic stage (highlighted with red lines), which shrinks with decreasing of temperature, and serrated flow at temperatures lower than 40K.

 

 

This work was funded within the frames of German Research Society Research Unit (Deutsche Forschungsgemeinschaft Forschergruppe) FOR 714 (IV98/1-1,2).

For more details see:

  • Contribution of grain boundary related strain accommodation to deformation of ultrafine-grained palladium

Yu. Ivanisenko, N.A. Enikeev, K. Yang, A. Smoliakov, V.P. Soloviev, H. Fecht, and H. Hahn

Mat. Sci. Eng. 2016 A668: 255–262

  • Variation of the deformation mechanisms in a nanocrystalline Pd - 10 at.% Au alloy at room and cryogenic temperatures

Yu. Ivanisenko, E.D. Tabachnikova, I.A. Psaruk, et al.

Int. Journal of Plasticity, 2014 60:40-57. DOI: 10.1016/j.ijplas.2014.04.011 http://www.int.kit.edu/img/intern/icon_external_link.gif.

 

 

 

 

 

 

 

5. Mechanical properties of nanocrystalline carbon steels under static and cyclic load

This is a collaborative research work with Chritian Kübel's group at INT KIT and Eberhard Kerscher's group at TU Kaiserslautern.  Our aim is to correlate the macroscopic mechanical behavior with the microstructural state of the nanocrystalline plain carbon steel with 0.45 wt.% C, to reveal the operative nanoscale deformation processes and to develop design criteria for the processing of technically feasible high-strength Fe-based nanostructured materials. High pressure torsion at elevated temperatures – warm HPT - is used to refine the ferrite grain size down to 120 nm (Fig. 5).

Figure 5. Microstructure of 0.45 wt.% C steel in as patented state (a,b), and after warm HPT (d,e). (a): SEM image; (b,d):ACOM TEM phase contrast image, ferrite is shown in red, and cementite in green color; (c) ACOM TEM orientation map.    

As processed steel demonstrated a record combination of strength and ductility: yield strength of ~1500 MPa, ultimate strength up to 2100 MPa and uniform elongation of 3.7% (Fig. 6). This level of ultimate tensile strength is greater than that of some grades of the advanced high strength steel and even martensitic steels.

 Figure 6. Tensile curves of C45 steel in as-patented state and after HPT processing at 350°C for 5 rotations. For details see: 
  • Tensile properties and work hardening behaviors of ultrafine grained carbon steel and pure iron processed by warm high pressure torsion

       J.L. Ning, E. Courtois-Manara, L. Kurmanaeva, A.V. Ganeev, R.Z. Valiev, C. Kübel, Yu. Ivanisenko

       Mat. Sci. Eng. 2013, A581:8-15. DOI: 10.1016/j.msea.2013.05.008 

  • Fatigue Behavior of Ultrafine-Grained Medium Carbon Steel with Different Carbide Morphologies Processed by High Pressure Torsion

C. Ruffing, A. Kobler, E. Courtois-Manara, R. Prang, C. Kübel, Yu. Ivanisenko, E. Kerscher

Metals 2015, 5:891-909

  • In-situ tensile test of high strength nanocrystalline bainitic steel

M. Haddad, Yu. Ivanisenko, E. Courtois-Manara, H.-J. Fecht

Mat. Sci. Eng. 2015, A620: 30-35.

This work was funded by German Research Society (Deutsche Forschungsgemeinschaft DFG) under contracts IV98/2-1, IV98/4-1.

Selected Publications

1. Wang, C; Guo, X; Ivanisenko, Y; et al.  Scripta Materialia, 139, 9-12, 2017, doi: 10.1016/j.scriptamat.2017.06.007

2. Nandam, S H; Ivanisenko, Yu; Schwaiger, R; et al.  Acta Materialia, 136, 181-189, 2017, doi: 10.1016/j.actamat.2017.07.001

3. Mohri, M; Wang, D; Ivanisenko, J; et al.  Materials Characterization, 131, 140-147, 2017,   doi: 10.1016/j.matchar.2017.07.014

4. Shaysultanov, D. G.; Salishchev, G. A.; Ivanisenko, Y. V.; et al.  Journal of Alloys and Compounds, 705, : 756-763, 2017,   doi: 10.1016/j.jallcom.2017.02.211

5. Macdonald, B. E.; Fu, Z.; Zheng, B.; et al.  JOM, 69 (10), 2024-2031, 2017,   doi: 10.1007/s11837-017-2484-6

6. Kilmametov, A.; Ivanisenko, Yu; Straumal, B.; et al.  Scripta Materialia, 136, 46-49, 2017,   doi: 10.1016/j.scriptamat.2017.04.010

7. Ivanisenko, Yu.; Enikeev, N. A.; Yang, K.; et al. Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing, 668, 255-262, 2016, doi: 10.1016/j.msea.2016.05.036

8. Ivanisenko, Yu.; Kulagin, R.; Fedorov, V.; et al.  Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing, 664, 247-256,  2016,   doi: 10.1016/j.msea.2016.04.008

9. Sniadecki, Z.; Wang, D.; Ivanisenko, Yu.; et al.  Materials Characterization, 113, 26-33, 2016, doi: 10.1016/j.matchar.2015.12.025

10. Wang, C; Wang, D; Mu, X; et al.  Materials Letters, 181, 248-252, 2016, doi: 10.1016/j.matlet.2016.05.189

 
 
 
 
 
 
 
 
 
 

11. Beygelzimer, Y; Kulagin, R; Toth, L S.; et al. Beilstein Journal of Nanotechnology, 7, 1267-1277,  2016, doi: 10.3762/bjnano.7.117

12. Ruffing, C; Kobler, A; Courtois-Manara, E; et al. Metals, 5 (2), 891-909, 2015, doi: 10.3390/met5020891

13. Haddad, M; Ivanisenko, Yu; Courtois-Manara, E; et al. Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing, 620, 30-35, 2015, doi: 10.1016/j.msea.2014.09.088

14. Straumal, B. B.; Kilmametov, A. R.; Ivanisenko, Yu.; et al. Advanced Engineering Materials, 17 (12), 1835-1841, 2015, doi: 10.1002/adem.201500143

15. Straumal, B. B.; Kilmametov, A. R.; Ivanisenko, Yu; et al. International Journal of Materials Research, 106 (7), 657-664, 2015, doi: 10.3139/146.111215

16. Straumal, B. B.; Kilmametov, A. R.; Mazilkin, A. A.; et al. Materials Letters, 138, 255-258, 2015, doi: 10.1016/j.matlet.2014.10.009

17. Zhong, Y; Markmann, J; Jin, H; et al. Advanced Engineering Materials, 16 (4), 389-398, 2014, doi: 10.1002/adem.201300211

18. Yang, K; Fecht, H; Ivanisenko, Yu. Advanced Engineering Materials, 16 (5), 517-521, 2014, doi: 10.1002/adem.201300413

19. Abramova, M. M.; Enikeev, N. A.; Valiev, R. Z.; et al.  Materials Letters, 136, 349-352, 2014, doi: 10.1016/j.matlet.2014.07.188

20. Straumal, B. B.; Kilmametov, A. R.; Ivanisenko, Y.; et al.  Materials Letters, 118, 111-114, 2014, doi: 10.1016/j.matlet.2013.12.042

21. Ivanisenko, Yu.; Tabachnikova, E. D.; Psaruk, I. A.; et al. International Journal of Plasticity, 60, 40-57, 2014, doi: 10.1016/j.ijplas.2014.04.011

22. Skrotzki, W.; Eschke, A.; Joni, B.; et al. Acta Materialia,61 (19), 7271-7284, 2013, doi: 10.1016/j.actamat.2013.08.032

23. Ivanisenko, Y; Werz, T; Minkow, A; et al. Journal of Materials Science, 48 (19), 6841-6847, 2013, doi: 10.1007/s10853-013-7490-7

24. Ning, J; Courtois-Manara, E; Kurmanaeva, L; et al. Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing, 581, 2013,  doi: 10.1016/j.msea.2013.05.008