Synthesis and characterization of high entropy (TiVNbTaM) <sub>2</sub>AlC (M = Zr, Hf) ceramics
Lei Cao, Qiqiang Zhang, Lijing Du, Shuai Fu, Detian Wan, Yiwang Bao, Qingguo Feng, Chunfeng Hu
Abstract
The high-entropy design of MAX phases is expected to confer superior properties, but its study was hindered by the complex synthesis method and limited purity of samples. In this work, two noteworthy types of high-entropy MAX phase structural ceramics, high-entropy (TiVNbTaM)<sub>2</sub>AlC (M = Zr, Hf), were designed and prepared by <em>in-situ</em> synthesis using spark plasma sintering (SPS). The microstructure and lattice parameters of sintered samples were determined. Compared with the single-component MAX phases, the highly pure high-entropy (TiVNbTaZr)<sub>2</sub>AlC sample had good physical and mechanical properties, including electrical conductivity of 0.96 × 10<sup>6</sup> Ω<sup>-1</sup>·m<sup>-1</sup>, thermal expansion coefficient of 3.65 × 10<sup>-6</sup> K<sup>-1</sup>, thermal conductivity of 8.98 W·m<sup>-1</sup>·K<sup>-1</sup>, Vickers hardness of 9.80 GPa, flexural strength of 507 MPa, fracture toughness of 5.62 MPa·m<sup>1/2</sup>·and compressive strength of 1364 MPa, which exhibited the remarkable hardening-strengthening effect.