Processing and characterisation of nano crystalline AlCoCrCuFeTi_x high-entropy alloy

ABSTRACT

In this work multi-component equiatomic and non-equiatomic AlCoCrCuFeTi_x hexanary high-entropy alloys (HEA) was synthesised through mechanical alloying. The prepared powder was sintered via spark plasma sintering. Influence of alloying element variation in the multi-component system was studied in terms of phase formation and crystal structure by using Thermo-Calc and X-ray diffraction characterization technique (XRD). Particle morphology and chemical analysis studies were carried out through scanning electron microscopy along with Electron Dispersive X-ray Spectroscopy. The crystal structure and nano crystallinity of the hexanary system were recognised using transmission electron microscope (TEM and Selected Area Electron Diffraction [SAED]) while the formation of a solid solution was also studied and discussed. From the XRD and TEM characterisation of 20 h in, milled powders and sintered samples, it was confirmed that the developed HEA system forms a single solid solution BCC phase. The sintered alloy exhibits 97% relative density and an average hardness of 590 VHN.

Special theme block on high entropy alloys, guest edited by Paula Alvaredo Olmos, Universidad Carlos III de Madrid, Spain, and Sheng Guo, Chalmers University, Gothenburg, Sweden.

KEYWORDS:

• High-entropy alloys
• mechanical alloying
• solid solution
• nano crystalline
• Thermo-Calc
• thermal analysis
• X-ray diffraction
• transmission electron microscope

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

M. Murali is the corresponding author, working in high-entropy alloy field.

S. P. Kumaresh Babu is Research supervisor and expert in composite materials, nanomaterials, and foundry engineering operations.

Jichil Majhi is co-research scholar expert in nanomaterials.

A. Vallimanalan is co-research scholar expert in powder metallurgy principles.

R. Mahendran is co-research scholar expert in thermal barrier coating materials.

ORCID

A. Vallimanalan http://orcid.org/0000-0003-0556-6567