Local control of microstructure and mechanical properties of high-strength steel in electric arc-based additive manufacturing

Aravind Babu*, Amin Ebrahimi, K. Wu, Ian M. Richardson, Marcel J.M. Hermans

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

4 Citations (Scopus)
68 Downloads (Pure)

Abstract

Additive manufacturing offers a significant potential for producing metallic parts with distinctly localised microstructures and mechanical properties, commonly known as functional grading. While functional grading is generally accomplished through compositional variations or in-situ thermo-mechanical treatments, variation of process parameters during additive manufacturing can offer a promising alternative approach. Focusing on the electric arc-based additive manufacturing process, this work focuses on the functional grading of high-strength steel (S690 grade) by adjusting the travel speed and inter-pass temperature. Through a combination of thermal simulations and experimental measurements on single bead-on-plate depositions, it is shown that the microstructure and the mechanical properties of parts can be controlled through the rational adjustment of process parameters. A rectangular block was fabricated to demonstrate functional grading using a constant wire feed rate and varying travel speed. The rectangular block consisted of a low heat input (LHI) region deposited between high heat input (HHI) zones. A graded microstructure was obtained with the HHI zones composed of a mixture of polygonal ferrite, acicular ferrite, and bainite, while the LHI region was primarily composed of martensite. The hardness and profilometry-based indentation plastometry measurements indicated that the LHI region exhibited higher hardness (32%) and strength (50%), but lower uniform elongation (80%), compared to the HHI zones. The present study demonstrates the potential to achieve functional grading by adjusting process parameters in electric arc-based additive manufacturing, providing opportunities for tailor-made properties in parts.

Original languageEnglish
Pages (from-to)1508-1526
JournalJournal of Materials Research and Technology
Volume26
DOIs
Publication statusPublished - 2023

Keywords

  • High-strength steel
  • Mechanical behaviour
  • Metal additive manufacturing
  • Microstructural control
  • Thermal modelling
  • Wire arc additive manufacturing (WAAM)

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