18-22 July 2016
Hotel Wyndham Grand Axelmannstein, Bad Reichenhall, Germany
Europe/Berlin timezone

Strain Induced Martensitic Transformation in Austempered Ductile Iron (ADI)

19 Jul 2016, 16:50
2h 40m
Hotel Wyndham Grand Axelmannstein, Bad Reichenhall, Germany

Hotel Wyndham Grand Axelmannstein, Bad Reichenhall, Germany

Salzburger Str. 2-6 83453 Bad Reichenhall
Board: 25
Poster Engineering & Industrial applications Poster Session

Speaker

Dr Michael Hofmann (FRM II, Technische Universität München)

Description

Austempered ductile iron (ADI) is a cast iron that has undergone a special heat treatment to greatly enhance mechanical properties. The heat treatment process of ADI consists of austenitization, quenching to a temperature between 250°C and 450°C and isothermal austempering [1, 2]. After such a heat treatment, the microstructure consists of acicular ferrite and high carbon enriched retained austenite. The high carbon enriched retained austenite can transform to martensite during plastic deformation. The treatment parameters (austenitization temperature, austempering temperature, austempering time and alloying composition) can influence the retained austenite fraction, grain size and its stabilisation [2], which in turn will influence the deformation induced martensitic transformation. The influence of different treatment and composition parameters on the martensitic transformation and texture formation during plastic deformation has been investigated using neutron diffraction. The combination of texture analysis and in-situ deformation tests allowed quantitative phase analysis and extraction of martensite phase fractions as a function of strain level. The experiments allowed us to determine the influenece of austempering temperature, Nickel content and plastic strain on the martensitic transformation kinetics in ADI. [1] L. Meier, M. Hofmann, P. Saal, W. Volk, H. Hoffmann, Mat. Char. 85 (2013) 124-133 [2] P. Saal, L. Meier, X. Li, M. Hofmann, M. Hoelzel, J.N. Wagner, W. Volk, Met. Mater. Trans A 47 (2016) 661-671 [2] Srinivasmurthy Daber et al, J.Mater.Sci (2008) 43:4929-4937

Primary author

Dr Michael Hofmann (FRM II, Technische Universität München)

Co-authors

Dr Markus Hoelzel (FRM II, Technische Universität München) Mr Patrick Saal (utg, Technische Universität München) Dr Weimin Gan (GEMS@MLZ, HZG) Mr Xiaohu Li (FRM II, Technische Universität München)

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