Self-healing behavior of Ti2AlC at a low oxygen partial pressure

Abstract

Ti2AlC, a MAX phase ceramic, has an attractive self-healing ability to restore performance via the oxidation-induced crack healing mechanism upon healing at high temperatures in air (high oxygen partial pressures). However, such healing ability to repair damages in vacuum or low oxygen partial pressure conditions remains unknown. Here, we report on the self-healing behavior of Ti2AlC at a low oxygen partial pressure of about 1 Pa. The experimental results showed that the strength recovery depends on both healing temperature and time. After healing at 1400 °C for 1–4 h, the healed samples exhibited the recovered strengths even exceeding the original strength of 375 MPa. The maximum recovered strength of ∼422 MPa was achieved in the healed Ti2AlC sample after healing at 1400 °C for 4 h, about 13% higher than the original strength. Damages were healed by the formed TiCx from the decomposition of Ti2AlC. The decomposition-induced crack healing as a new mechanism in the low oxygen partial pressure condition was disclosed for the MAX ceramics. The present study illustrates that key components made of Ti2AlC can prolong their service life and keep their reliability during use at high temperatures in low oxygen partial pressures.

Oxidation‐induced crack‐healing behavior of SiC‐Al2O3‐TiB2 composites at 600°C–800°C

“…12,13 Many investigations have been carried out in the past on silicon carbide ceramics, [14][15][16][17][18][19][20] silicon nitride ceramics, [21][22][23] and MAX phase ceramics. [24][25][26][27][28][29][30][31][32][33] These studies have also shown that oxidation mechanism can greatly improve the mechanical properties and service life of the damaged ceramics with better healing effects. However, most of the oxidation-induced self-healing ceramics due to the slow healing rate and high healing temperature is still difficult to meet certain service requirements.…”

“…In the oxidation healing mechanism, some components of the ceramic react with oxygen at a certain temperature to produce volume expansion, and the resulting oxide phase has a certain fluidity to fill and repair cracks, thus greatly restoring material properties 12,13 . Many investigations have been carried out in the past on silicon carbide ceramics, 14–20 silicon nitride ceramics, 21–23 and MAX phase ceramics 24–33 . These studies have also shown that oxidation mechanism can greatly improve the mechanical properties and service life of the damaged ceramics with better healing effects.…”

Self‐lubricating effect of solid solution elements on tribological performance of Ti3AlC2 over a wide temperature range

“…The self‐formation of mixed oxides offers the potential for properties recovery by crack healing of MAX phases in high temperatures of 800–1200°C under aerobic environment. More worthy of attention is that Cr 2 AlC and Ti 2 SnC are lately demonstrated with self‐crack healing ability in low oxygen partial pressures and decreased temperatures 21–26 . Additionally, attractive tribological characteristics have been considerably developed, which are primarily associated with the self‐lubricating oxidation‐introduced friction film on the worn surface, along with the dramatic high‐temperature performance and mechanical properties making MAX phases potentially advantageous as solid lubricants in aerospace, high‐speed trains, or marine environment applications with extreme service conditions 4,27–31 …”

“…More worthy of attention is that Cr 2 AlC and Ti 2 SnC are lately demonstrated with selfcrack healing ability in low oxygen partial pressures and decreased temperatures. [21][22][23][24][25][26] Additionally, attractive tribological characteristics have been considerably developed, which are primarily associated with the self-lubricating oxidation-introduced friction film on the worn surface, along with the dramatic high-temperature performance and mechanical properties making MAX phases poten-tially advantageous as solid lubricants in aerospace, highspeed trains, or marine environment applications with extreme service conditions. 4,[27][28][29][30][31] Present research indicated that partial substitution treatment on the M, A, and X sites can be used to modify the mechanical properties of resulted materials due to the solid solution hardening and strengthening effects, as well as to tailor the tribological performance by providing controllable phase composition and oxide proportion of the predominate friction film.…”

Influence of nano-mechanical evolution of Ti 3AlC 2 ceramic on the arc erosion resistance of Ag-based composite electrical contact material

“…This ensures enhanced performance, particularly in maintaining lower contact resistance and minimized temperature increases during the service process. In addition, it is established that the A-Ag interdiffusion behavior of Ag/MAX composite induced by preparing and arc temperature assists in improving the interfacial bonding and mechanical properties [19,30].…”