Common mechanism for controlling polymorph selection during crystallization in supercooled metallic liquids

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal

2 Scopus Citations
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Author(s)

  • Simin An
  • Rui Su
  • Yuan-Chao Hu
  • Jianbo Liu
  • Baixin Liu
  • Pengfei Guan

Detail(s)

Original languageEnglish
Pages (from-to)367-373
Journal / PublicationActa Materialia
Volume161
Online published26 Sep 2018
Publication statusPublished - Dec 2018

Abstract

Despite the fundamental and technological importance, the physical scenario of polymorph selections during crystallization in metals remains poorly understood. Here, through the extensive molecular dynamics simulation, we study the crystallization pathway of face-centered cubic (fcc) metals aluminum and copper. We reveal two different crystallization pathways at ambient pressure: involving the metastable body-centered cubic (bcc) polymorph (Cu) or not involving the bcc polymorph (Al). Interestingly, by varying pressure on Al, we successfully control polymorph selection and observe crystallites containing the metastable bcc polymorph. These findings are in line with the phonon dispersion analyses, which indicate that the bcc structure of Cu at ambient pressure and of Al at high pressure remain stable whereas that of Al at low pressure is thermally unstable. More importantly, we demonstrate that it is the profile of the free energy surface related to the phase stability, rather than the strong cohesive interactions of metals, encodes the crystallization pathway in metals. Our findings not only shed important light on a common thermodynamic mechanism of polymorph selections, but also pave a new way for better controlling the crystallization pathway in industrial and metallurgical applications by regulating the stability of the intermediate metastable phases.

Research Area(s)

  • Controlling, Crystallization, Free energy surface, Polymorph selection, Stability

Citation Format(s)

Common mechanism for controlling polymorph selection during crystallization in supercooled metallic liquids. / An, Simin; Su, Rui; Hu, Yuan-Chao; Liu, Jianbo; Yang, Yong; Liu, Baixin; Guan, Pengfei.

In: Acta Materialia, Vol. 161, 12.2018, p. 367-373.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal