Discrete model for discontinuous dynamic recrystallisation applied to grain structure evolution inside adiabatic shear bands

Elijah Borodin, Oleg Bushuev, Vladimir Bratov, Andrey Jivkov

Research output: Contribution to journalArticlepeer-review

Abstract

Discontinuous dynamic recrystallisation (DDRX) is a well-known phenomenon playing a significant role in the high-temperature processing of metals, including industrial form- ing and severe plastic deformations. The ongoing discussion on the Zenner-Hollomon (Z-H) parameter as a descriptor of materials’ propensity to DDRX and a measure of microstructure homogeneity leaves more questions than answers and prevents its practical application. Most of the existing DDRX models are continuous, and so the geometry and topology of real grain microstructures cannot be considered. The present study uses a fully discrete representation of polycrystalline aluminium alloys as 2D/3D Voronoi space tessellations corresponding to EBSD maps. Such tessellations are geometric reali- sations of combinatorial structures referred to as polytopal cell complexes. Combining discrete models with FEM LS-Dyna simulations of shock-wave propagation in AA1050 and AW5083 aluminium alloys makes it possible to estimate for the first time the contri- bution of DDRX to the final material microstructure inside adiabatic shear bands. It is shown that the increase of the initial fraction of high-angle grain boundaries, caused by preliminary deformation, significantly increases the spatial homogeneity and decreases the clustering of DDRX grains. The obtained results contradict the conventional assumption that the microstructures obtained by severe plastic deformation under quasi-static and dynamic deformation conditions are similar due to the similar value of the Z-H parameter: competition between the two recrystallisation mechanisms leads to almost unpredictable final grain structures inside share bands that require further comprehensive experimental studies. This agrees with experimental experimental evidence for high material sensitivity to the Z-H parameter.
Original languageEnglish
Pages (from-to)2125-2139
Number of pages15
JournalJournal of Materials Research and Technology
Volume30
Early online date1 Apr 2024
DOIs
Publication statusE-pub ahead of print - 1 Apr 2024

Keywords

  • discontinuous dynamic recrystallization
  • adiabatic shear bands
  • aluminium alloys
  • high strain rates
  • polytopal cell complex
  • FEM

Research Beacons, Institutes and Platforms

  • Advanced materials

Fingerprint

Dive into the research topics of 'Discrete model for discontinuous dynamic recrystallisation applied to grain structure evolution inside adiabatic shear bands'. Together they form a unique fingerprint.

Cite this