Growth of a brittle crack (0 0 1) in 3D bcc iron crystal with a Cu nano-particle

• Crack growth with a Cu particle in front of the crack in bcc Fe is studied via MD.
• Sample geometry and loading of the crack (0 0 1) is the same as in pure bcc Fe.
• The crack penetrates Cu nano-particle via cleavage but later retards in front of Cu.
• Crack front wave arises in Fe–Cu system unlike pure bcc Fe with straight front.
• Wave patterns emitted on crack faces in Fe–Cu are corrugated as well.

We present new results of molecular dynamics (MD) in 3D bcc Fe–Cu crystal with embedded central through crack (0 0 1)[1 1 0] of Griffith type loaded in mode I. Such sample geometry and border conditions in MD were chosen to invoke a cleavage crack extension through a bcc Cu nano-particle placed in front of the crack. The stress field and bond breakage caused by the crack and Cu inhomogeneity are analysed on the atomistic level. The character of crack extension and corresponding wave patterns are studied in the Fe–Cu system. The study is motivated by a question how a small Cu bcc precipitate changes the brittle behavior of the crack in comparison with pure bcc iron loaded in mode I.

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