Microstructure and bending behavior of Ti/Al laminated composites reinforced with high-entropy alloy particles

Abstract

Ti/Al laminated composites embedded with Al0.5CoCrFeNi high entropy alloy particles were prepared by vacuum hot press sintering process at temperatures of 660 °C and 730 °C. The microstructure of the material was initially examined using XRD, SEM, EDS, EBSD, and TEM techniques. The results of microstructural characterisation show that Al3Ti is the only newly generated phase in the materials prepared at two temperatures. The Al3Ti generated at the temperature of 660 °C is concentrated at the Ti/Al interface position. The Al3Ti generated at a temperature of 730 °C is dispersed in the Al matrix, leading to the formation of numerous Al3Ti/Al interfaces. The residual HEA particles were observed at the sites of oxide aggregation, potentially enhancing the connectivity of the weak interfaces. Following that, the flexural strength and fracture toughness of the composites were evaluated. The results indicate that the materials prepared at a temperature of 730 °C exhibit superior properties. The flexural strength perpendicular to the layer direction reaches 515.89 MPa, while the flexural strength parallel to the layer direction reaches 487.1 MPa. These findings demonstrate clear anisotropy in the flexural performance. Additionally, the material exhibits excellent resistance to crack extension, with a fracture toughness of 32.67 MPa√m.