Microstructure and magnetic properties evolution of Al/CoCrFeNi nanocrystalline high‐entropy alloy composite
Junjie Wang, Zongde Kou, Shu Fu, Shangshu Wu, Sinan Liu, Mengyang Yan, Di Wang, Si Lan, Horst Hahn, Tao Feng
Abstract
Abstract A systematic microstructure‐oriented magnetic property investigation for Al/CoCrFeNi nanocrystalline high‐entropy alloys composite (nc‐HEAC) is presented. In the initial state, the Al/CoCrFeNi nc‐HEAC is composed of face‐centered cubic (FCC)‐Al, FCC‐CoCrFeNi and hexagonal close‐packed (HCP)‐CoNi phases. High energy synchrotron radiation X‐ray diffraction and high‐resolution transmission electron microscopy were used to reveal the relationship between microstructure evolution and magnetic mechanism of Al/CoCrFeNi nc‐HEAC during heat treatment. At low‐temperature annealing stage, the magnetic properties are mainly contributed by the HCP‐CoNi phase. With the increase of temperature, the diffusion‐induced phase transition process including the transformation of AlCoCrFeNi HEA from FCC to BCC structure and the growth of B2 phase plays a dominant role in the magnetic properties. It was found that the magnetic properties can be effectively regulated through the control of the thermal diffusion process. The nano dual‐phase thermal diffusion‐induced phase transition behavior of nanocomposites prepared based on laser‐IGC technology provides guidance for the diffusion process and microstructure evolution of two phases in composites.