Aluminide Coatings on Titanium-based Alloy IMI-834 for High Temperature Oxidation Protection

Md. Zafir Alam; Dipak K. Das

doi:10.14429/dsj.61.477

Md. Zafir Alam Defence Metallurgical Research Laboratory, Hyderabad
Dipak K. Das Defence Metallurgical Research Laboratory, Hyderabad

DOI: https://doi.org/10.14429/dsj.61.477

Keywords: Coatings, oxidation, titanium, IMI-834 alloy, near-alpha titanium alloy, Aluminide, Pt-aluminide, Aluminide coatings

Abstract

Microstructural aspects and cyclic oxidation behaviour of plain aluminide and Pt-aluminide coatings on the near-a Ti-alloy IMI-834 have been studied. Both the coatings provide good oxidation resistance to the above alloy at 650 °C, 750 °C, and 850 °C. However, significant cracking develops in the coatings during coating formation as well as during cyclic oxidation exposure. The extent of cracking during oxidation is found to increase with the exposure temperature. Presence of through-thickness cracks in the coatings leads to localised oxidation damage of the underlying substrate at all the three temperatures. At 850 °C, such localised oxidation generates enough TiO2 so that this oxide phase grows through the cracks and emerges at the sample surface forming a clearly identifiable mud-crack pattern. The extent of such oxidation damage is comparatively much lower at 750 °C and 650 °C.

Defence Science Journal, 2011, 61(2), pp.180-190, DOI:http://dx.doi.org/10.14429/dsj.61.477

Author Biographies

Md. Zafir Alam, Defence Metallurgical Research Laboratory, Hyderabad

Mr Md Zafir Alam obtained his BTech (Metallurgical Engineering) from National Institute of Technology, Rourkela and is presently pursuing his PhD from Indian Institute of Science (IISc), Bengaluru. Presently working in the Surface Engineering Group, Defence Metallurgical Research Laboratory(DMRL), Hyderabad. He has published/communicated over 15 papers in peer-reviewed journals in various national/international conferences. His research interests are development and processing of thermal barrier coatings for aero-engine and other high temperature applications, evaluating the mechanical behaviour of coated superalloys, micro-mechansims of fracture in freestanding coatings and coated superalloys.

Dipak K. Das, Defence Metallurgical Research Laboratory, Hyderabad

Dr Dipak Kumar Das obtained his BTech (Hons) in Metallurgical Engineering from Indian Institute of Technology, Kharagpur and PhD from Banaras Hindu University, Banaras. Presently, he is working as Scientist 'F' at DMRL, Hyderabad. His research interests include: High temperature coatings for aeroengine, space and hypersonic applications, laser-material interaction and laser surface modification of materials, and plasma-particle interaction in plasma spray process. He has over 50 technical publications to his credit in international peer-reviewed journals.