Low-Temperature Criticality of Martensitic Transformations of Cu Nanoprecipitates in alpha-Fe
Journal article, 2013

Nanoprecipitates form during nucleation of multiphase equilibria in phase segregating multicomponent systems. In spite of their ubiquity, their size-dependent physical chemistry, in particular, at the boundary between phases with incompatible topologies, is still rather arcane. Here, we use extensive atomistic simulations to map out the size-temperature phase diagram of Cu nanoprecipitates in alpha-Fe. The growing precipitates undergo martensitic transformations from the body-centered cubic (bcc) phase to multiply twinned 9R structures. At high temperatures, the transitions exhibit strong first-order character and prominent hysteresis. Upon cooling, the discontinuities become less pronounced and the transitions occur at ever smaller cluster sizes. Below 300 K, the hysteresis vanishes while the transition remains discontinuous with a finite but diminishing latent heat. This unusual size-temperature phase diagram results from the entropy generated by the soft modes of the bcc-Cu phase, which are stabilized through confinement by the alpha-Fe lattice.

Author

Paul Erhart

Chalmers, Applied Physics, Materials and Surface Theory

B. Sadigh

Physical Review Letters

0031-9007 (ISSN) 1079-7114 (eISSN)

Vol. 111 2 025701- 025701

Subject Categories

Physical Sciences

Other Physics Topics

Metallurgy and Metallic Materials

Condensed Matter Physics

Infrastructure

C3SE (Chalmers Centre for Computational Science and Engineering)

Areas of Advance

Materials Science

DOI

10.1103/PhysRevLett.111.025701

More information

Latest update

4/5/2022 6