Fcc→bcc→hcp successive phase transformations in the strained ultrathin copper film: A molecular dynamic simulation study

• Published in: Materials chemistry and physics Vol. 223; pp. 171 - 182
• Main Authors: Sun, Bin, Ouyang, Wenze, Ren, Jijiang, Mi, Liwei, Guo, Wei
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.02.2019; Elsevier BV
• Subjects: Copper; Crystallography; Film thickness; Martensitic transformations; Metal films; Molecular dynamic simulation; Molecular dynamics; Nanometer Cu film; Parents; Phase transformation; Phase transitions; Simulation; Stretching; Tensile stress; Uniaxial tensile strain; Phase transformation; Nanometer Cu film; Molecular dynamic simulation; Uniaxial tensile strain
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2018.09.045

The phase transformation behaviors of ultrathin Cu film under uniaxial tensile stress are investigated using molecular dynamic simulation. With the stress increasing, Cu film undergoes a successive phase transformation, i.e. firstly fcc→bcc, then bcc→hcp. The phase transformation process is very fast and thorough, i.e., all parents phase can transit into the new phase almost instantaneously. The crystallography mechanisms of two martensitic transformations are exactly corresponding to Bain and Burgers mechanism, respectively. By examining the formation conditions of such phase transformation in Cu film, we reveal that this fcc→bcc→hcp successive phase transformation will be subject to the very strict simulation conditions, namely stretching along [100] （or [010], [001]）direction, definitive tensile speed (1 × 1010/s), appropriate film thickness (0.7230–18.08 nm), low temperature (T ≤ 10 K), and continuous stretching process without any relaxation procedure. •A fcc →bcc→hcp successive phase transformations are discovered during the Cu film stretching.•Very fast and thorough phase transformation process.•The two phase transformations are consist with Bain and Burgers mechanisms.•The successive phase transformations occur only under very strict conditions.