Effect of temperature on the healing capacity and mechanical properties of Ti₂AlC MAX phase ceramics

Abstract

In this study, the self-healing capacity of Titanium Aluminum Carbide (Ti₂AlC, MAX phase) was investigated. Bulk coin samples were fabricated to evaluate the self-healing capacity at different temperatures (1000, 1200, and 1400°C). The extensive self-healing capacity of Ti₂AlC was confirmed on larger quasiplastic damage (diameter ≥1 mm) and radial cracks by covering and filling of oxides such as titanium oxide, aluminum oxide, and aluminum titanate oxide. Although the mechanical properties of Ti₂AlC after healing are similar or improved relative to the Ti₂AlC before healing at the microscale, some properties of Ti₂AlC after introducing larger damage and healing at 1400°C showed reduced values due to excessive oxide formation on the surface. For example, the strength of Ti₂AlC healed at 1400°C exhibited 151.4 MPa, which is relative to the original strength of 298.3 MPa. Alternatively, the mechanical properties such as strength, hardness, toughness, and relative modulus of elasticity of Ti₂AlC healed at 1000 or 1200°C and were restored to their original strength after healing. These findings suggest that Ti₂AlC can be used as a healing agent for high-temperature applications, such as environmental barrier coating for gas turbine hot-gas components.