Research

Current projects as Principal Investigator: Fatigue behavior of nanostructured bainite (German Research Foundation (DFG) Research Grants. Project number 411091845) Nanostructured bainite, in its first stages of its industrialization, is one promising advance steel because of its simplicity in terms of alloy design and processing, and its outstanding mechanical properties, having achieved the highest strength-toughness combinations ever recorded in bainitic steels (2.2GPa-30MPa · m1 / 2). Before the potential application of this alloy in advance components such as bearing, gears or railway systems, the study of mechanical fatigue, ie, material's response to cyclic loading is essential. There are several reasons motivating a detailed study of the effect of the microstructure on the fatigue response in nanostructured bainite. First of all, monotonic properties fail to explain the fatigue performance, which is not improved by increasing the strength and the ductility. Second, a conventional approach to predict the lifetime based on SN 'curves (stress v. Number of cycles) does not make distinctions between crack nucleation and propagation, which may lead to dangerous overestimates of life. Finally, and likewise, at the short crack regime, the crack growth rate is not explained by the Linear Elastic Fracture Mechanics (LEFM), ie, the propagation speed may be higher than that of long cracks. It is before crack nucleation and during short crack regimes when the local microstructure controls the fatigue response. So far, a global effective grain size has not been found. Morphological parameters associated with the bainite block might be controlling the intrinsic fatigue limit of these microstructures, but the question about the effect of the microstructure on the fatigue life at different stress levels remains unsolved. The relationship between the crack deflection at certain grain boundaries and the crack arrest, which can contribute to enhance the fatigue life, has not been established either. The role of the second phase, the retained austenite, remains also unknown. This project is intended to gain new knowledge on the nature of the bainitic structure, ie, grain boundaries, mechanically induced phase transformation and defects evolution before the crack nucleation and along the crack path. The deformation and damage mechanisms will be treated in combination with the cyclic plastic hardening / softening behavior and correlated with the different stages of the fatigue crack growth. For that purpose, both advanced experimental techniques based on microscopy and diffraction and theoretical approaches will be applied and developed. It will enable the assessment of the relative importance that this evolving microstructure has on the fatigue life. As a result, an improved fatigue design in terms of safety will be possible. It will enable the assessment of the relative importance that this evolving microstructure has on the fatigue life. As a result, an improved fatigue design in terms of safety will be possible. It will enable the assessment of the relative importance that this evolving microstructure has on the fatigue life. As a result, an improved fatigue design in terms of safety will be possible.

Project leading:

• Since 2018: German National Project „Ermüdungsverhalten nanostrukturierter Bainite“, funded by the Deutsche Forschungsgemeinschaft (German Research Foundation), Ref. MO 3311/2-1.  
• 2017-2018: "Charakterisierung und mechanische Eigenschaften von Vortex-Verbundwerkstoffen mit UFG-Gefüge", financially supported by the TU-Nachwuchsring of the University of Kaiserslautern.

   

Personal Details

• 03/2011 - 11/2015: Pre-doctoral research associate at the department of physical metallurgy (CENIM-CSIC, Madrid, Spain)
• Since 12/2015: Post-doctoral research associate at Working Group Materials Testing

Publications

• L. Morales-Rivas, G. Sundaram:
  Parent austenite reconstruction tolerant to 180° ambiguity: Application to a very-high-cycle fatigue tested bearing-steel.
  Mater. Charact., 178 (2021) 111253.

• A. Eres-Castellanos, J. Hidalgo, L. Morales-Rivas, F.G. Caballero, C. Garcia-Mateo:
  The role of plastic strains on variant selection in ausformed bainitic microstructures studied by finite elements and crystal plasticity simulations.
  Journal of Materials Research and Technology, 13 (2021) 1416-1430.

• S. Kieren-Ehses, L. Böhme, L. Morales-Rivas, J. Lösch, B. Kirsch, E. Kerscher, M. Kopnarski, J.C. Aurich:
  The influence of the crystallographic orientation when micro machining commercially pure titanium: A size effect.
  Precis. Eng., 72 (2021) 158-171.

• A. Eres-Castellanos, L. Morales-Rivas, J.A. Jimenez, F.G. Caballero, C. Garcia-Mateo:
  Effect of Ausforming on the Macro- and Micro-texture of Bainitic Microstructures.
  Metall. Mater. Trans. A, 52 (2021) 9: 4033-4052.

• Lucia Morales-Rivas, Farangis Ram, Daniel Spriestersbach, Jan Sippel, Marc De Graef, Eberhard Kerscher:
  Fine granular area linked to very high cycle fatigue in martensitic and bainitic steels: characterization by means of EBSD-dictionary indexing.
  Scripta Materialia 194 (2021), 113644.

• A Eres-Castellanos, L Morales-Rivas, FG Caballero, C Garcia-Mateo:
  Explaining the dilatometric behavior during bainite transformation under the effect of variant selection.
  Journal of Alloys and Compounds, (2020),158130.

• L Morales-Rivas, L Böhme, E Kerscher:
  Orientation mapping of cp-Ti by reflected polarized light microscopy.
  MATEC Web of Conferences 321 (2020), 11096.

• L Morales-Rivas:
  Graphically Assisted Dynamical Subsetting of Crystal Orientation Maps Using MTEX–MATLAB.
  Metallography, Microstructure, and Analysis 4 (2019), 558-565.

• FG Caballero, R Rementeria, L Morales-Rivas, M Benito-Alfonso, J R Yang, D Castro, J D Poplawsky, T Sourmail, C Garcia-Mateo:
  Understanding mechanical properties of nano-grained bainitic steels from multiscale structural analysis.
  Metals 9 (2019), 426.

• A. Eres-Castellanos, L. Morales-Rivas, A. Latz, F.G. Caballero, C. Garcia-Mateo:  
  Effect of ausforming on the anisotropy of low temperature bainitic transformation.  Mater. Charact., (2018) 145: 371-380.

• L. Morales-Rivas, F. Archie, S. Zaefferer, M. Benito-Alfonso, S.-P. Tsai, J.-R. Yang, D. Raabe, C. Garcia-Mateo, F.G. Caballero:  
  Crystallographic examination of the interaction between texture evolution, mechanically induced martensitic transformation and twinning in nanostructured bainite.  J. Alloys Compd., (2018) 752: 505-519.

• L. Böhme, L. Morales-Rivas, S. Diederichs, E. Kerscher: 
  Crystal c-axis mapping of hcp metals by conventional reflected Polarized Light Microscopy: Application to untextured and textured cp-Titanium. Materials Characterization 145 (2018) 573-581.(https://doi.org/10.1016/j.matchar.2018.09.024)

• L. Morales-Rivas, S. Diederichs, L. Böhme, E. Gordo, A. Hebestreit, E. Kerscher: 
  Method for the detection of grain boundaries in alpha Ti-based alloys by means of polarized light microscopy and image processing in MATLAB. Practical Metallography, 55 (2018) 10, 678-692.

• Sourmail, C. Garcia-Mateo, F.G. Caballero, L. Morales-Rivas, R. Rementeria, M. Kuntz:
  Tensile ductility of nanostructured bainitic steels: influence of retained austenite stability
  Metals (2017) 7 (1). doi:10.3390/met7010031.

• R. Rementeria, F.G. Caballero, L. Morales-Rivas, C. Garcia-Mateo:
  Developing nanostructured metal at the atomic and nano scales
  Advanced Materials and Processes (2017) 21. mio.asminternational.org/amp/201701/.

• F.G. Caballero, J.D. Poplawsky, H.W. Yen, R. Rementeria, L. Morales-Rivas, J.R. Yang, C. García-Mateo:
  Complex Nano-Scale Structures for Unprecedented Properties in Steels
  Mater. Sci. Forum (2017) 879: 2401-2406.

• L. Morales-Rivas, C. Garcia-Mateo, T. Sourmail, M. Kuntz, R. Rementeria, F.G. Caballero:
  Ductility of Nanostructured Bainite
  Metals (2016) 6: 302. doi: 10.3390/met6120302.

• C. Garcia-Mateo, J.A. Jimenez, B. Lopez-Ezquerra; R. Rementeria; L. Morales-Rivas, M. Kuntz, F.G. Caballero:
  Analyzing the scale of the bainitic ferrite plates XRD, SEM and TEM
  Materials Characterization (2016) 122: 83-89.

• C. Garcia-Mateo, L. Morales-Rivas, F.G. Caballero, D. Milbourn, T. Sourmail:
  Vanadium Effect on a Medium Carbon Forging Steel
  Metals (2016) 6 (130) doi:10.3390/met6060130.

• L. Morales-Rivas, C. Garcia-Mateo, Matthias Kuntz, Thomas Sourmail, F.G. Caballero:
  Induced martensitic transformation during tensile test in nanostructured bainitic steels
  Mater. Sci. Eng. A (2016) 662: 169:177.

• L. Morales-Rivas, H.-W. Yen, B.-M. Huang, M. Kuntz, F.G. Caballero, J.-R. Yang, C. Garcia-Mateo:
  Tensile response of two nano-scale bainite composite-like structures
  JOM (2015) 67 (10): 2223-2235.

• L. Morales-Rivas, A. González-Orive, C. Garcia-Mateo, A. Hernández-Creus, F.G. Caballero, L. Vázquez:
  Nanomechanical characterization of nanostructured bainitic steel: Peak Force Microscopy and Nanoindentation with AFM
  Scientific Reports (2015) 5: 17164. DOI: 10.1038/srep17164.

• C. Garcia-Mateo, J.A. Jimenez, H.W. Yen, M.K. Miller, L. Morales-Rivas, M. Kuntz, S.P. Ringer, J.R. Yang, F.G. Caballero:
  Low temperature bainitic ferrite: Evidence of carbon super-saturation and tetragonality
  Acta Mater. (2015) 91:162-173.

• R. Rementeria, L. Morales-Rivas, M. Kuntz, C. Garcia-Mateo, E. Kerscher, T. Sourmail, Francisca G. Caballero:
  On the role of microstructure in governing the fatigue behaviour of nanostructured bainitic steels
  Mater. Sci. Eng. A (2015) 630:71-77.

• L. Morales-Rivas, F.G. Caballero, C. Garcia-Mateo:
  Chapter “Retained Austenite: Stability in a Nanostructured Bainitic Steel.”
  Encyclopedia of Iron, Steel and Their Alloys (2016) 1st. Ed. ISBN 9781466511040 - CAT# K14814

• L. Morales-Rivas, H. Roelofs, St. Hasler, C. Garcia-Mateo, F.G. Caballero:
  Detailed characterization of complex banding in air-cooled bainitic steels
  J. Min. Metall. Sect. B-Metall (2015) 51 (1) B.

• R. Rementeria, I. García, L. Morales-Rivas, M. Kuntz, C. Garcia-Mateo, E. Kerscher, T. Sourmail, F.G. Caballero:
  On the relationship of microstructure and in-use properties of nanostructured bainitic steels
  ISSIJ, ISBN 978-4-930980-86-1 C3057.

• L. Morales-Rivas, V.A. Yardley, C. Capdevila, C. Garcia-Mateo, H. Roelofs, F.G. Caballero:
  A procedure for indirect and automatic measurement of prior austenite grain size in bainite/martensite microstructures
  J. Mater. Sci. (2015) 50: 258–267.

• C.-M. Lin, A.S. Chandra, L. Morales-Rivas, S.-Y. Huang, H.-C. Wu, Y.-E. Wu, H.-L. Tsai:
  Repair welding of ductile cast iron by laser cladding process: microstructure and mechanical properties
  Int. J. Cast. Metal. Res.(2014) 27(6):378-383.

• L. Morales-Rivas, H. Roelofs, St. Hasler, C. Garcia-Mateo, F. G. Caballero:
  Complex microstructural banding of continuously cooled carbide-free bainitic steels
  Mater. Sci. Forum (2014) 783-786: 980.

• S.S. Babu, S. Vogel, C. Garcia-Mateo, B. Clausen, L. Morales-Rivas, F.G. Caballero:
  Microstructure evolution during tensile deformation of a nanostructured bainitic steel
  Scr. Mater. (2013) 69: 777-780.

• B. Avishan, C. Garcia-Mateo, L. Morales-Rivas, S. Yazdani, F.G. Caballero:
  Strengthening and mechanical stability mechanisms in nanostructured bainite
  J. Mater. Sci. (2013) 48: 6121–6132.

• L. Morales-Rivas, C. García-Mateo, F.G. Caballero, J. Cornide:
  Efecto TRIP y ductilidad en aceros bainíticos nanoestructurados
  (2012) ISBN: 978-84-695-3316-1.

Presentations

• E. Gordo, L. Morales-Rivas, L. Böhme, E. Kerscher, S.A. Tsipas, L. Bolzoni (V):
  Fatigue and oxidation behavior of low-cost PM Ti-Fe alloys
  PMTi, 4th International Conference on Titanium Powder Metallurgy & Additive Manufacturing, 2017, Xi’an (P.R. China).
• F. Ram (V), L. Morales-Rivas, S. Singh, B. Winiarski, T. Burnett, A. Gholinia, M. De Graef:
  Improved spatial and angular resolution of the Electron Backscatter Diffraction technique for measuring highly deformed and fine-grained materials
  MS&T, Materials Science & Technology, 2017, Pittsburgh, PA, (USA).
• L. Morales-Rivas (V), I. Mueller, R. Rementeria, M. Kuntz, T. Sourmail, F.G. Caballero, C. Garcia-Mateo, E. Kerscher:
  Fatigue governed by microstructure in nanostructured bainite
  EUROMAT, European Congress and Exhibition on Advanced Materials and Processes, 2017, Thessaloniki (Greece).
• M. Benito-Alfonso, S.-P. Tsai, J.-R. Yang, R. Rementeria, L. Morales-Rivas, C. García-Mateo, F. G. Caballero (V):
  Enhancing strain hardening in ultra-fine and nanostructured ultra-high strength bainitic steels
  EUROMAT, European Congress and Exhibition on Advanced Materials and Processes, 2017, Thessaloniki (Greece).
• L. Morales-Rivas, S. Diederichs, L. Böhme, E. Gordo, A. Hebestreit (V), E. Kerscher:
  Methode zur Erkennung von Korngrenzen in alpha-Ti-Basislegierungen mittels polarisierter Lichtmikroskopie und Bildverarbeitung mit MATLAB
  51. Metallographie-Tagung, Materialographie, 2017, Aalen (Germany).
• L. Böhme (V), L. Morales-Rivas, C. Godard, E. Kerscher:
  Deformation and fracture of specimens with structured surfaces
  International Conference on Microscale Morphology of Component Surfaces, MICOS, 2016, Kaiserslautern (Germany).
• I. Müller (V), L. Morales-Rivas, M. Kuntz, R. Rementeria, F.G. Caballero, E. Kerscher:
  Nanobainitischer Stahl: Korrelation zwischen Mikrostruktur und Ermüdungseigenschaften
  “Gemeinschaftsarbeitskreis Materialermüdung und Verformung und Bruch”, Deutsche Gesellschaft für Materialkunde (DGM) und Deutscher Verband für Materialforschung und –prüfung (DVM), 2016, Kaiserslautern (Germany).
• F.G. Caballero (V), J.D. Poplawsky, H.W. Yen, R. Rementeria, L. Morales-Rivas, J.R. Yang and C. Garcia-Mateo:
  Complex Nano-Scale Structures for Unprecedented Properties in Steels
  THERMEC, International Conference on Processing and Manufacturing of Advanced Materials. Processing, fabrication, properties, applications, 2016, Graz (Austria).
• L. Morales-Rivas (V), R. Rementeria, F.G. Caballero, C. Garcia-Mateo:
  Microestructura y respuesta mecánica de aceros bainíticos nanoestructurados
  XIV Congreso Nacional de Materiales, 2016, Gijón (Spain).
• M. Benito-Alfonso (V), R. Rementería, L. Morales-Rivas, C. García-Mateo, F. G. Caballero:
  Estudio de los mecanismos de deformación (efecto TRIP y efecto TWIP) de aceros bainíticos nanoestructurados con un alto contenido en austenita
  XIV Congreso Nacional de Materiales, 2016, Gijón (Spain).
• L. Morales-Rivas, A. González-Orive, C. Garcia-Mateo, A. Hernández-Creus, F.G. Caballero1, L. Vázquez (V):
  Nanoindentation with AFM and Peak Force Microscopy analyses for local elastoplastic characterization of nanostructured bainitic steel
  Advances in Materials&Processing Technologies Conference, 2015, Madrid (Spain).
• R. Rementeria (V), L. Morales-Rivas, I. Garcia, C. Garcia-Mateo, M. Kuntz, E. Kerscher, R. Janisch, F.G. Caballero:
  On the relationship of microstructure and in use properties of nanostructured bainitic steels
  ISSS, 4th International Symposium in Steel Science, 2014, Kyoto (Japan).
• L. Morales-Rivas (V), B.M. Huang, H.W. Yen, C. Garcia-Mateo, J.R. Yang, M. Kuntz, F.G. Caballero:
  Ductility and TRIP Effect in Nanostructured Bainite
  ICOMAT, International Conference on Martensitic Transformations, 2014, Bilbao (Spain).
• R. Rementeria (V), L. Morales-Rivas, M. Kuntz, E. Kerscher, C. Garcia-Mateo, F.G. Caballero:
  Fatigue resistance in Nanobainitic steels
  ICOMAT, International Conference on Martensitic Transformations, 2014, Bilbao (Spain).
• C. Garcia-Mateo (V), M.K. Miller, H.W. Yen, J.A. Jimenez, J.R. Yang, L. Morales-Rivas, F.G. Caballero:
  Experimental evidence on tetragonality of low temperature bainitic ferrite
  ICOMAT, International Conference on Martensitic Transformations, 2014, Bilbao (Spain).
• L. Morales-Rivas (V), C. Garcia-Mateo, J.R. Yang, M. Kuntz, F.G. Caballero:
  Efecto TRIP y ductilidad en aceros bainíticos nanoestructurados
  XIII Congreso Nacional de Materiales, 2014, Barcelona (Spain).
• R. Rementeria (V), L. Morales-Rivas, M. Kuntz, E. Kerscher, C. Garcia-Mateo, F.G. Caballero:
  Comportamiento a fatiga de aceros bainíticos nanoestructurados
  Congreso Nacional de Materiales, 2014, Barcelona (Spain).
• B. López Ezquerra (V), L. Morales-Rivas, C. García-Mateo, F.G. Caballero:
  Influencia de la transformación martensitica en la cinética de formación de bainita nanoestructurada
  Congreso Nacional de Materiales, 2014, Barcelona (Spain).
• F.G. Caballero (V), M.K. Miller, H.W. Yen, J.A. Jimenez, C. Garcia-Mateo, L. Morales-Rivas, J.R. Yang:
  Carbon Super-saturation and Tetragonal Bainitic Ferrite in Nanocrystalline Bainitic Steels
  TMS, Annual Meeting and Exhibition, Symposium: Phase Transformation and Microstructural Evolution, 2014, San Diego (California, USA).
• L. Morales-Rivas, H. Roelofs (V), St. Hasler, C. Garcia-Mateo and F. G. Caballero:
  Complex microstructural banding of continuously cooled carbide-free bainitic steels
  THERMEC, International Conference on Processing and Manufacturing of Advanced Materials, 2013, Las Vegas (USA).
• B. Avishan, L. Morales-Rivas, C. Garcia-Mateo (V), S. Yazdani, F.G. Caballero:
  Describing TRIP effect for two nanostructured bainitic steels
  EUROMAT, European Congress and Exhibition on Advanced Materials and Processes, 2013, Sevilla (Spain).
• L. Morales-Rivas (V), C. García-Mateo, F.G. Caballero, J. Cornide:
  Efecto TRIP y ductilidad en aceros bainíticos nanoestructurados
  XII Congreso Nacional de Materiales / XII Congreso Iberoamericano de Materiales, 2012, Alicante (Spain).

Poster

• L. Böhme, L. Morales-Rivas, E. Kerscher:
  Mechanische Eigenschaften mikrostrukturierter Ti-Miniaturproben unter zyklischer Belastung
  12. Tagung Gefüge und Bruch, Bochum, 13.-15. Februar 2019

Supervised Student Research Projects

• Steffen Sarter: Automatic crystallographic parent reconstruction of martensite / bainite with MATLAB / MTEX (2018)
• S. Diederichs: Crystallographic orientation characterization of Titanium by polarized light microscopy (2017)
• A. Weimann: Determination of the film normal in the transmission electron microscope and application to the published crystallography of TWIP steels (2017)
• M. Berger: Understanding the influence of the crystal orientation of hcp crystals on the contrast in the polarizing microscope (2016)
• R. Rementeria: In-use properties of nanostructured bainitic steels (CENIM-CSIC, Madrid, 2014)