Improving the plasticity of a high strength Fe-Si-Ti ultrafine composite by introduction of an immiscible element

摘要

A heterostructured Fe_(71)Si_(15)Ti_(10)Cu_4 ultrafine composite has been developed. The addition of Cu with large positive enthalpy of mixing with the main constituent element (Fe) leads to evolution of a unique microstructure with different length-scale heterogeneities, i.e., formation of spherical colonies containing length-scale heterogeneity of lamellar spacing and precipitation of nanoscale multitwinned Cu within a-Fe layers. These macroscopic and microscopic structural heterogeneities are able to simultaneously achieve high strength and plasticity, together with pronounced work hardening by avoiding the deformation instability