Hardening steels by the generation of transient phase using additive manufacturing

E-Wen Huang*, Soo Yeol Lee, Jayant Jain, Yang Tong, Ke An, Nien-Ti Tsou, Tu Ngoc Lam, Dunji Yu, Hobyung Chae, Shi Wei Chen, Shih Min Chen, Hung Sheng Chou

*Corresponding author for this work

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

In the present work, the tensile properties of 15–5 PH steel fabricated by selective laser melting (SLM) were examined with respect to the transient austenite phase. Compared with the 8%-transient-phase sample, the 18%-transient-phase one shows higher ultimate tensile strength and relatively low yield strength, as well as hardening behavior. We conducted in-situ neutron-diffraction study to examine the microstructure evolution for mechanistic understanding. After applying the external load, most non-equilibrium, retained austenite in the 8%-transient-phase sample transforms before the yield strength, whereas in the 18%-transient-phase sample only 50% of the austenite transforms. Accompanying with the phase transformation, a decrease in the dislocation density and the dislocation strain energy-assisted phase transformation of the ferrite phase are found in the 8%-transient-phase sample even before yielding, which, however, is not the case in the 18%-transient-phase sample. The study demonstrates the SLM enables tuning the amount of transient-phase ratio and coherency between phases to realize a mechanical property control for additive manufactured steel.

Original languageEnglish
Pages (from-to)60-67
Number of pages8
JournalIntermetallics
Volume109
DOIs
StatePublished - Jun 2019

Keywords

  • Neutron diffraction
  • Additive manufacturing
  • Selective laser melting
  • Stainless steel
  • Anisotropy
  • SITU NEUTRON-DIFFRACTION
  • MECHANICAL-PROPERTIES
  • DISLOCATION-STRUCTURE
  • AUSTENITE
  • DEFORMATION
  • MARTENSITE
  • PROFILE
  • TRANSFORMATION
  • ALLOY

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