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Bainitic variant evolution in a low‐alloyed steel including numerical aspects
Author(s) -
Ehlenbröker Ulrich,
Mahnken Rolf
Publication year - 2014
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.201410178
Subject(s) - bainite , austenite , convergence (economics) , transformation (genetics) , quenching (fluorescence) , martensite , work (physics) , yield (engineering) , materials science , plasticity , volume fraction , phase (matter) , set (abstract data type) , finite element method , component (thermodynamics) , metallurgy , thermodynamics , computer science , chemistry , microstructure , composite material , physics , biochemistry , organic chemistry , quantum mechanics , economics , fluorescence , gene , programming language , economic growth
Bainite formation is of particular industrial relevance especially after hot‐forming and quenching of relatively bulky components. In these processes large portions of the component are subjected to appropriate cooling rates which yield a considerable fraction of the bainitic product phase. In our work, we develop a thermodynamically consistent multi‐scale model for phase transformations from austenite into 24 possible bainite variants. Furthermore, the model is capable to express the macroscopic effects of volume change due to phase transformation as well as to transformation‐induced plasticity (TRIP). Basic ideas for our material‐model can be found among others in [1–3]. Because of the highly complex, strongly coupled model equations, the numerical implementation is a very challenging task. Therefore, we make use of a projected Newton algorithm combined with an active‐set strategy, as an extension to the approach in [4] for austenite‐martensite transformations in shape memory alloys. Numerical examples illustrate the quadratic convergence behaviour in a Finite‐Element scheme. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)