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Study of high temperature mechanical behavior of the thermally oxidized Ti‐6Al‐4V alloy
Author(s) -
B. P. Severino,
Antônio Augusto Couto,
Danieli Aparecida Pereira Reis,
C. Aguiar,
Mariano Castagnet,
C. Moura Neto
Publication year - 2014
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/mawe.201400226
Subject(s) - materials science , oxide , ultimate tensile strength , alloy , brittleness , layer (electronics) , composite material , metallurgy , substrate (aquarium) , fracture (geology) , oceanography , geology
The influence of oxidation of a Ti‐6Al‐4V alloy at 800 °C on its tensile properties at 600 °C has been studied. Specimens of this alloy were oxidized at 800 °C for 0.5, 1, 5, 10, 20 and 40 h. Tensile tests at 600 °C were carried out and the fracture surfaces were also examined. Oxidation of the specimens resulted in the formation of an oxide layer that spalled and another oxide layer that adhered to the substrate. Oxide formation increased with increase in duration of oxidation. In this investigation, density curves of the oxide layer as a function of duration of oxidation at 800 °C were used to identify a parabolic oxide growth law. The results of this study revealed coherence between the experimental data and calculations based on the Pilling‐Bedworth law. The mechanical strength of the Ti‐6Al‐4V alloy did not vary significantly with oxidation, but reduction in cross sectional area with increase in oxide layer thickness, as well as the slope of the stress‐strain curve decreased beyond the ultimate tensile strength. Fracture of the tensile tested specimens was predominantly ductile with microcavities. At certain regions of the oxide layer, brittle fracture with radial cracks was observed indicating intergranular fracture.