Hydrogen-induced deformation and damage micro-mechanisms in titanium (22/12/25)”
Speaker and Affliation:
Prof. Nilesh P. Gurao
Professor, Department of Materials Science and Engineering, Indian Institute of Technology Kanpur, Kanpur, India
When?
22nd December, 2025 (Monday), 4.00 PM (India Standard Time)
Where
KPA Auditorium, Dept. of Materials Engineering, IISc, Bangalore
Abstract:
The present study examines the influence of hydrogen on the deformation behavior of commercially pure (CP) titanium under uniaxial loading. Tensile specimens machined along the transverse direction in the normal plane were electrochemically charged with hydrogen and subsequently homogenized at 573 K for 12 hours in an argon atmosphere to achieve a uniform hydrogen distribution across the specimen thickness. Tensile tests conducted at a strain rate of 10-3 s-1 revealed an increase in both yield and ultimate tensile strengths, accompanied by a marginal reduction in ductility for the hydrogen-charged samples. Analysis of the strain-hardening response indicated delayed twin nucleation occurring at higher stress levels in the hydrogenated condition. Full-field strain mapping using 2D digital image correlation (DIC) demonstrated pronounced strain localization in the hydrogen-charged specimens. Fractographic observations further revealed a transition from ductile dimpled fracture surfaces in uncharged samples to quasi-brittle fracture features in charged samples, characterized by decohesive regions and cracks arising from strain incompatibility due to hydride formation along grain boundaries. To uncover the underlying micro mechanisms, in situ tensile experiments were performed within a field emission scanning electron microscope (FESEM) under both imaging and electron back scatter diffraction (EBSD) modes. EBSD analyses showed a greater density of extension and contraction twins in hydrogen-charged specimens, confined to basal-oriented grains, while other grains exhibited limited deformation accommodation. The intergranular misorientation analysis and slip trace analysis further provided information on the change in slip activity and grain boundary cracking in the hydrogen charged samples. The critical role of crystallographic texture and temperature on deformation behaviour of titanium in the presence of hydrogen in terms of deformation and damage mechanisms will be elaborated.
With contributions from: Shirish Chandrakar (IITK) and Poorwa Gore (AiChemy (OPC) Private Limited, Kanpur)
Speaker Bio:
Prof. Nilesh P. Gurao is a professor in the Department of Materials Science and Engineering at the Indian Institute of Technology Kanpur (IIT Kanpur). He received his Ph.D. in Materials Engineering from the Indian Institute of Science, Bangalore in 2010, and a B.E. in Metallurgical Engineering from VNIT Nagpur in 2005. His research focuses on the mechanical behavior of materials, crystallographic texture and thermo-mechanical processing, often combining experiments with crystal-plasticity simulations. Prior to joining IIT Kanpur, he worked as a research associate at IISc Bangalore and as a postdoctoral fellow at the University of Saskatchewan in Canada (2010–2012). He has been recognized with honors including the INSA Young Scientist Medal and the Young Metallurgist of the Year award (2015).