Partially amorphous nanocomposite obtained from heavily deformed pearlitic steel

Cold-drawn pearlitic steel wires are known to exhibit increasing strength with increasing elongation and are therefore highly interesting for a wide field of engineering applications. In a combined high-resolution transmission electron microscopy and atom probe tomography study, the strengthening mechanism is elucidated: first, there is a strong fragmentation of the original pearlitic microstructure, followed by partial decomposition of cementite accompanied by amorphization of the latter, leading to dispersion hardening. The concomittent mechanisms are discussed in detail.