Assoc. Prof. Dr. Daniel Kiener

Function: Group Leader
Room: 412
Phone: +43 (0) 3842-804-412
E-Mail: daniel.kiener(at)unileoben.ac.at

 

Research

Micro- and Nanomechanics and Micro- and Nanostructure Characterization

When the material grain size or the sample volume itself are reduced to the micron- and sub-micron regime, significant size effects on the mechanical properties arise due to the increased contribution of surfaces and interfaces. We aim to derive a mechanistic understanding of the interplay between sample or microstructure size, the presence of individual microstructural elements such as interfaces, grain boundaries or dislocations, and the resulting global material properties. This is achieved by a combination of sophisticated methods such as highly localized and miniaturized quantitative experiments performed within high-resolution electron microscopy techniques, temperature- and rate dependent thermo-mechanical microstructure analysis, and advanced nanoindentation techniques. Various interests in the field of Micro- and Nanomechanics concern:

  • Miniaturized testing techniques (compression, tension, bending, fracture, fatigue, ...)
  • Small scale sample preparation techniques
  • Quantitative electron microscopy
  • Size effects influencing material properties
  • Dislocation plasticity in confined volumes
  • Deformation mechanisms in nanoscale or nanostructured materials (slip, twinning, grain boundaries)
  • Irradiation resistant materials by microstructural design
  • Temperature dependent deformation mechanisms of single crystal and nanocrystalline fcc and bcc metals
  • Thermal fatigue behavior and microstructural stability of metallic thin films
  • Local depth-dependent residual stresses in complex layered structures
  • Fracture processes and properties of small structures and multilayers
  • Deformation mechanisms in hexagonal metals
  • Temperature dependent deformation mechanisms in nanoporous materials

 

Methods

Size effects influencing material properties, dislocation plasticity in confined volumes, temperature and irradiation dependent deformation, thermal fatigue and fracture of small-scale structures and multilayers, in-situ micromechanical testing in the SEM, in-situ nanomechanical testing in the TEM, advanced nanoindentation techniques, digital image correlation methods

 

  • In situ micromechanical experiments in the SEM
  • In situ nanomechanical testing in the TEM
  • Broad ion beam and FIB based material structuring
  • Advanced nanoindentation techniques (e.g. elevated temperatures, rate dependencies)
  • Digital image correlation techniques to measure local deformations and microstructural evolution
  • Local determination of residual stresses with high depth resolution
  • Miniaturized fracture testing in the SEM and TEM
  • Novel laser-based fast thermo-mechanical heating/cycling techniques

 

Teaching

In-situ an In-operando Characterization Techniques in Materials Science (In-situ und in-operando Charakterisierungstechniken in der Werkstoffwissenschaft), Materialphysik I and III, Wissenschaftliche Arbeiten in der Materialphysik

 

  • Introduction to Materials Science
  • Materials Characterization
  • Materials Physics I
  • Materials Physics III
  • Exercises to Materials Physics
  • In-situ and in-operando characterization techniques in material science
  • Exercises to In-situ and in-operando characterization techniques in material science
  • Seminar Bachelor Thesis
  • Seminar Master Thesis
  • Scientific Work in Materials Physics

Publications

  • High-speed nanoindentation mapping of organic matter-rich rocks: A critical evaluation by correlative imaging and machine learning data analysis
    S. Vranjes-Wessely, D. Misch, D. Kiener, M. Cordill, N. Frese, A. Beyer, B. Horsfield, C. Wang, R. Sachsenhofer
    Int. Journal of Coal Geology247, ARTN 103847 (2021)
  • High-speed nanoindentation mapping of organic matter-rich rocks: A critical evaluation by correlative imaging and machine learning data analysis
    S. Vranjes-Wessely, D. Misch, D. Kiener, M. Cordill, N. Frese, A. Beyer, B. Horsfield, C. Wang, R. Sachsenhofer
    Int. Journal of Coal Geology247, ARTN 103847 (2021)
  • In-situ TEM investigation of toughening in Silicon at small scales
    I. Issa, C. Gammer, S. Kolitsch, A. Hohenwarter, P. Imrich, R. Pippan, D. Kiener
    Materials Today47, ARTN 1369-7021 (2021)
  • How grain boundary characteristics influence plasticity close to and above the critical temperature of ultra-fine grained bcc Ta2.5W
    J. Kappacher, O. Renk, D. Kiener, H. Clemens, V. Maier-Kiener
    Acta Materialia216, 117110 (2021)
  • In situ fracture observations of distinct interface types within a fully lamellar intermetallic TiAl alloy
    M. Burtscher, M. Alfreider, K. Schmuck, H. Clemens, S. Mayer, D. Kiener
    jmr36, 2465-2478 (2021)
  • Disordered interfaces enable high temperature thermal stability and strength in a nanocrystalline aluminum alloy
    G. Balbus, J. Kappacher, D. Sprouster, F. Wang, J. Shin, Y. Eggeler, T. Rupert, J. Trelewicz, D. Kiener, V. Maier-Kiener, D. Gianola
    Acta Materialia215, ARTN 116973 (2021)
  • Zr addition-dependent twin morphology evolution and strengthening response in nanostructured Al thin films
    G. Li, Y. Wang, J. Zuo, M. Zhang, C. He, X. Feng, J. Luan, Y. Lu, J. Zhang, S. Cazottes, D. Kiener, G. Liu, J. Sun
    Materialia16, ARTN 101076 (2021)
  • Initiation of fatigue damage in ultrafine grained metal films
    O. Glushko, D. Kiener
    Acta Materialia206, ARTN 116599 (2021)
  • Extracting information from noisy data: strain mapping during dynamic in situ SEM experiments
    M. Alfreider, M. Meindlhumer, V. Maier-Kiener, A. Hohenwarter, D. Kiener
    jmr11, 2291-2304 (2021)
  • Prospects of Using Small Scale Testing to Examine Different Deformation Mechanisms in Nanoscale Single Crystals - A Case Study in MG
    D. Kiener, J. Jeong, M. Alfreider, R. Konetschnik, S. Ho Oh
    crystals11, ARTN: 11010061 (2021)