+358 40 849 0142
+358 40 849 0142
I am responsible of the research services and the infrastructure of Tampere Wear Center and the materials characterization facilities. In addition, I work as a coordinator of Wear Forum that is a collaboration network between TWC, research institutes, and companies. My particular research interests are the high stress abrasive and impact wear of steels, characterization of wear mechanisms, and assessment of the relevance of laboratory wear test methods in regard of the in-service performance of steels and other wear resistant materials. I have over 60 peer-reviewed scientific articles and about 70 other scientific publications, including conference papers with h-index 16 (Scopus).
Societal Interaction Council of Tampere University, member, 2019-
Faculty Council of Engineering and Natural Sciences, member, 2019-
Tribologia - Finnish Journal of Tribology, editor, 2012-
Finnish Society for Tribology, board member, 2014-
Organiziner of the annual TWC International Wear Seminar 2009-
Valtonen, K., Ojala, N., Haiko, O., Kuokkala, V.-T. Comparison of various high-stress wear conditions and wear performance of martensitic steels, Wear 426–427:3-13(2019).
Chintha, A.R., Valtonen, K. Kuokkala, V.-T., Kundu, S. Peet, M., Bhadeshia, H.K.D.H. Role of fracture toughness in impact-abrasion wear, Wear 428–429:430-437(2019).
Valtonen, K., Ratia, V., Ramakrihnan, K.R., Apostol, M., Terva, J., Kuokkala, V.-T., Impact wear and mechanical behavior of steels in subzero conditions. Tribology International 129:476-493(2019).
Valtonen, K., Keltamäki, K., Kuokkala, V.-T., High-stress abrasion of wear resistant steels in the cutting edges of loader buckets, Tribology International 119: 707–720(2018).
Valtonen, K., Ratia, V., Ojala, N., Kuokkala, V.-T., Comparison of laboratory wear test results with the in-service performance of cutting edges of loader buckets, Wear 388-389:93-100(2017).
Ojala, N., Valtonen, K., Minkkinen, J. & Kuokkala, V.-T. Edge effect in high speed slurry erosion wear tests of steels and elastomers, Wear 388-389:126-135(2017).
Ojala N., Valtonen K., Antikainen, A., Kemppainen, A., Minkkinen, J., Oja, O., Kuokkala V.-T. Wear performance of quenched wear resistant steels in abrasive slurry erosion, Wear 354-355:21-31(2016).
Oksanen, V., Valtonen, K., Andersson, P., Vaajoki, A., Laukkanen, A., Holmberg, K. & Kuokkala, V. T. 2015. Comparison of laboratory rolling-sliding wear tests with in-service wear of nodular cast iron rollers against wire ropes, Wear 340-341:73-81(2015).
Lindroos, M., Valtonen, K., Laukkanen, A., Holmberg, K., Kuokkala, V-T., Kemppainen, A., Wear behavior and work hardening of high strength steels in high stress abrasion, Wear 322-323:32-40(2015).
Ojala, N., Valtonen K., Heino V., Kallio M., Aaltonen J., Siitonen P. & Kuokkala, V.-T., Effects of composition and microstructure on abrasive wear performance of quenched wear resistant steels, Wear 317(1–2): 225–232(2014).
Ojala, N., Valtonen, K., Kivikytö-Reponen, P., Vuorinen, P., Siitonen, P. & Kuokkala, V.-T., The effect of test parameters on large particle high-speed slurry erosion testing, Tribology - Materials, Surfaces & Interfaces 8(2):98-104(2014).
Ratia, V., Valtonen, K., Kemppainen, A., Vippola, M., Kuokkala, V.-T., High-Stress Abrasion and Impact-Abrasion Testing of Wear Resistant Steels, Tribology Online 8(2):152-161(2013).
My research focus is on tribology, which investigates the friction, wear and lubrication of contacting surfaces as well as related fundamental failure mechanisms. This gives basis to provide advanced tribological expertise and solutions for developing future design concepts for machine elements and frictional joints to improve their performance, service life and operation monitoring. This work is done with close collaboration with industry using high standard numerical and experimental methods. Main current research interests are fretting induced friction, wear and fatigue in frictional joints as well as lubricated rolling/sliding contacts in gears and bearings related to combustion engines, mineral crushers and gear drives in wind turbines and marine applications. Advanced tribological contact design improves energy efficiency, power density and reliability of machine elements and systems having essential contribution to Finnish industrial competiveness and sustainable development.
Tribology (friction, wear and lubrication) and tribological machine elements in general - focusing on
- Fretting induced friction, wear and fatigue in frictional joints
- Lubricated rolling/sliding contacts in machine elements such as gears and bearings
Materials Science and Environmental Engineering
Professor, Materials Science, Tribology and Machine Elements, 2014 –
Professor, TUT, Machine Design, Mechanical Power Transmission and Tribology, 1999 –2013
Docent – Tribology, TUT, 1997-2002
R&D and Project Manager in private sector 1989-1996
Dr. Tech., TUT (Tampere University of Technology), 1989
Corresponding member: International Tribology Council (ITC), 2001-
Member of Nordic Scientific Advisory Board: NORDTRIB conference series, 2000 –
Bayat R., Lehtovaara A., EHL/mixed transition of fully formulated environmentally acceptable gear oils, Tribology International 146 (2020) 12 p., 106158.
Hintikka J., Mäntylä A., Vaara J., Frondelius T., Lehtovaara A., Stable and unstable friction in fretting contacts, Tribology International, 131 (2019) 73-82.
Nurmi V., Hintikka J., Juoksukangas J., Honkanen M., Vippola M., Lehtovaara A., Mäntylä A., Vaara J., Frondelius T., The formation and characterization of fretting-induced degradation layers using quenched and tempered steel. Tribology International 131 (2019) 258-267.
Juoksukangas J., Lehtovaara A., Mäntylä A., Experimental and numerical investigation of fretting fatigue behavior in bolted joints, Tribology International 103 (2016) 440-448.
Linjamaa A., Lehtovaara A, Larsson R., Kallio M, Söchting S., Modelling and Analysis of Elastic and Thermal Deformations of a Hybrid Journal Bearing. Tribology International 118 (2018) 451-457.
Savolainen M., Lehtovaara A., An approach to investigating subsurface fatigue in a rolling/sliding contact, International Journal of Fatigue 117 (2018) 180-188
Kleemola J., Lehtovaara A., Experimental simulation of gear contact along the line of action, Tribology International 42 (2009) 1453-1459.
I have Professorship (Tenured) in Materials Characterization. My research areas include microstructural characterization and NDT (non-destructive testing) of various materials together with activities in material prosessing, performance and failure analysis. My special expertise area is on electron microscopy including the leadership in university-level microscopy infrastructure (Tampere Microscopy Center). I also act as Vice Dean for Research in Faculty of Engineering and Natural Sciences.
Materials Science and Environmental Engineering
1. Professor (tenured), Tampere University 2019-
2. Professor (tenured) (2016 - 2018) Tampere University of Technology
3. Associate professor (tenure track) (2013 - 2016) Tampere University of Technology
4. Senior Researcher (fulltime/part time, 2007 - 2013) Finnish Institute of Occupational Health, Work Environment Development
5. Visiting Researcher (1999) Stockholm University, Structural Chemistry, Arrhenius Laboratory
6. Visiting Scholar (1996) University of Illinois at Urbana-Champaign, Frederick Seitz Materials Research Laboratory
7. Researcher/Senior Researcher/Senior Research Fellow (1996 – 2013) Tampere University of Technology
Pofessor (tenured) of Metals technology, research group leader. My research area includes processing and developing of metals and alloys, physical metallurgy, novel heat treatments, high entropy alloys, and more generally relationship between microstructure and material properties. Recent research topics have been formable ultra high strength thin sheet steels for automotive industry, heat treatment of tool steels, hot stamping of steel and aluminium alloys and processing maps of high entropy alloys. In addition to above topics, due to mys 20 years experience in workshop and steel industy, I co-operate with industry on various material issues.
International Deep Drawing Research Group (IDDRG), Executive committee 2011 -
Heat Treatment and Forging Branch Group member 2014 -
Aluminium Product Branch Group member 2017 -
National standardization committee K 900 “Steels and mechanical testing”, member
finddrg member 2014 -
Finnish Association of Mining and Metallurgical Engineers, board member 2016 – 2019
Curtze, S., Kuokkala, V-T., Hokka, M., Peura, P., “Deformation Behavior of TRIP and DP Steels in Tension at Different Temperatures over a Wide Range of Strain Rates”, Materials Science and En-gineering A. Vol. 507, no. 1-2, p124-131 (2009) DOI: 10.1016/j.msea.2008.11.050
Nyyssönen, T., Isakov, M., Peura, P. and Kuokkala V.-T.,”Iterative Determination of the Orientation Relationship Between Austenite and Martensite/Bainite from a Large Amount of Grain Pair Misorientations”, Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, Vol. 47, No. 6, 2016, p. 2587-2590
Järvinen, H., Isakov, M., Nyyssönen, T., Järvenpää, M., Peura, P., “The effect of initial microstructure on the final properties of press hardened 22MnB5 steels”, Materials Science & Engineering A 676, p. 109–120, 2016
Nyyssönen, T., Peura, P., Kuokkala, V.-T., “Crystallography, Morphology and Martensite Transformation of Prior Austenite in Intercritically Annealed High-Aluminium Steel”, Metallurgical and Materials Transactions A, 49 (12), pp. 6426-6441, 2018 https://doi.org/10.1007/s11661-018-4904-9
Patnamsetty, M., Somani, M.C., Ghosh, S., Ahmed, S., Peura, P., "Processing map for controlling microstructure and unraveling various deformation mechanisms during hot working of CoCrFeMnNi high entropy alloy", Materials Science and Engineering: A, VOL 793, 139840, 2020 https://doi.org/10.1016/j.msea.2020.139840.