ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Influence of the oxidation behavior of Ti–6Al–4V alloy in dry air on the oxide layer microstructure

Lamiaa Z. Mohamed, S. S. Abd Elmomen, and Shimaa El-Hadad

Mining, Petroleum, and Metallurgical Engineering Department, Faculty of Engineering, Cairo University, Giza, Egypt

E-mail: lamiaa.zaky@cu.edu.eg

Received: 3 August 2021  Accepted: 5 November 2021

Abstract:

The effects of isothermal oxidation parameters on the oxidation kinetics and morphology of the oxides layers obtained on Ti–6Al–4V alloy (Ti64) at 650, 750 and 850 °C for 50 h in dry air were studied. Morphology of the oxide scales was examined by scanning electron microscopy (SEM) and the energy-dispersive X-ray analysis (EDX). The phases in the scales were characterized by X-ray diffraction. The rate of oxidation at the different temperatures was described by a parabolic equation, and the oxidation activation energy value was 191.7 kJ/mol. The parabolic rate constants were 8.80 × 10^–9, 7.48 × 10^–8 and 7.68 × 10^–7 g²/(cm⁴.h) at 650 °C, 750 °C and 850 °C, respectively. The morphologies through the cross section of the oxide layers were analyzed by SEM, spot and line EDX. The analysis of the oxide scale revealed mainly TiO₂ and small amount of Al₂O₃. The oxide layers were discontinuous and non-protective layers at 750 °C and 850 °C.

Keywords: High-temperature oxidation; Ti–6Al–4 V alloy; Microstructure; Activation energy

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-021-01976-2

Chemical Papers 76 (3) 1627–1638 (2022)