Proceedings of the Third International Conference on Metals & Hydrogen L01

The Influence of Compositional and Microstructural Variations on Hydrogen Absorbance and Tensile Properties at Elevated Hydrogen Levels for TRIP-Aided Bainitic Ferrite Steels.

A. L. Bollinger (1)1 , T. Murakami (2)2 , K. O. Findley (1)1 , E. De Moor (1)1 , J. G. Speer (1)1

  • (1) 1

    Colorado School of Mines Department of Metallurgical and Materials Engineering

  • (2) 2



The influence of composition and microstructure on susceptibility to hydrogen embrittlement (HE) was investigated using a series of four experimental transformation-induced plasticity-aided bainitic ferrite (TBF) sheet steels. The TBF steels were designed to have similar carbon equivalency values (Ceq) and tensile strengths despite having significant variation in carbon and manganese content and microstructure. Quasi-static tensile tests at various pre-charged hydrogen concentrations were performed on the series of alloys to characterize susceptibility to HE. Decrease in ductility due to HE was associated with the degree of hydrogen absorption. The microstructure of each alloy was characterized using electron back-scatter diffraction (EBSD) and x-ray dispersive spectroscopy (XRD) and correlated to hydrogen absorption behavior. Greater amounts of microstructural attributes such as austenite (γ) and martensite/austenite (MA) island volume fraction, boundary area, and increased γ aspect ratio related to increased hydrogen absorption. Increased γ and MA content, resulting in increased untempered martensite volume fraction after deformation, correlated to decreased ductility at comparable diffusible hydrogen concentrations.


  • Hydrogen Embrittlement
  • Quasi-Static Tensile Properties
  • TRIP-Aided Bainitic Ferrite Steel
  • Untempered Martensite
  • Austenite Morphology