High-temperature mechanical properties and thermal shock behavior of ternary-layered MAB phases Fe ₂ AlB ₂

The high-temperature flexural and compressive strengths, and thermal shock behavior in water of Fe ₂ AlB ₂ were investigated from room-temperature (RT) to 1000 °C. The flexural strength varies in a narrow range of 200–250 MPa from room temperature to 1000 °C, without evident plastic deformation. The compressive strength of Fe ₂ AlB ₂ decreases gradually from 1992 ± 176 MPa at RT to 1482 ± 127 MPa at 600 °C. However, the further increasing temperature results in quicker decrease of the compressive strength to 245 ± 7 MPa at 1000 °C although no plastic deformation is present in the temperature range of 600–800 °C. The brittle-ductile transition temperature (BDTT) is higher under flexure (>1000 °C) than compression (800–900 °C), which is attributed to the higher shear stress under compression. The water-quenched flexural strength exhibits features consistent with the quasi-static propagation of “long initial cracks” with a critical temperature difference of 200–300 °C. The deduced cracks contribute to the decreasing retained strength. The uniaxial compress during hot pressing results in a weak anisotropy of mechanical properties.