• Studied the effects of various stresses on the TiAl/Ti₂AlC coating failure • Revealed interface corrosion behaviour at corrosion layer-Ti₂AlC and TiAl-Ti₂AlC • Stress causes the corrosion layer thickness to increase linearly • Stress causes an exponential increase in the crack count within the coating • Cracks initiate in Al-depleted regions The Ti₂AlC MAX phase coating is expected to become one of the potential protective coatings for aircraft compressor blades because of its excellent resistance to thermal corrosion. Considering the stresses imparted to blades by structural design, it is urgent to elucidate the mechanism by which stress influences the interfacial corrosion behaviour of Ti₂AlC coatings. In this paper, a four-point bending beam stress loading method was employed to investigate the corrosion behavior of TiAl/Ti 2 AlC coatings with solid salt deposition under 600 °C + water vapor environments. Results show that stress caused an increase in the thickness of the corrosion product film and the number of cracks within the TiAl/Ti₂AlC coatings, following linear and parabolic laws, respectively. The applied stress promotes the internal diffusion of Cl and O along the crack path towards the Ti₂AlC side of the TiAl-Ti₂AlC interface within the coating. The synergistic effect of Cl cycling and the activation-oxidation mechanism accelerates the depletion and outward migration of Al, leading to cracking initiation in Al-depleted zones, fracture at the TiAl-Ti₂AlC interface, and coating failure.
Xu et al. (Fri,) studied this question.