|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Advanced High-Strength Steels
||Deformation-Induced Martensite: A Thermodynamic Study
||Gh. Ali Nemaollahi, Soundes Djaziri, Yujiao Li, Blazej Grabowski, Christoph Kirchlechner, Aleksander Kostka, Shoji Goto, Dierk Raabe, Gerhard Dehm, Jörg Neugebauer
|On-Site Speaker (Planned)
Cold-drawn pearlitic steel wires revealing ultra-high tensile strengths of up to 7 GPa are the world’s strongest steels. Experimental observations reveal that cementite gradually decomposes during wire drawing. The C atoms resulting from the cementite decomposition are mechanically alloyed into the ferrite phase and accommodated in trapping sites around defects, such as dislocations. Surprisingly, there is also a high oversaturation of the bulk ferrite phase and experiments indicate a transformation to a tetragonally distorted system. We have therefore developed an ab initio informed model that accurately takes into account the interaction of C with the wire-drawn strained host matrix. The effect of the applied strain is captured by introducing a renormalized C formation energy and computing it by density functional theory. Applying the model we demonstrate that the experimentally observed tetragonal distortion is due to a mechanically driven phase transformation from ferrite (bcc) to martensite (bct).
||Planned: Supplemental Proceedings volume