Novel Multicomponent B2-Ordered Aluminides: Compositional Design, Synthesis, Characterization, and Thermal Stability

G Mohan Muralikrishna,A Carmel Mary Esther,K Guruvidyathri,Gerhard Wilde,Sergiy V Divinski,B S Murty,Philipp Watermeyer,Christian H Liebscher,Kaustubh N Kulkarni

doi:10.3390/met10111411

Abstract

For the first time, multicomponent alloys belonging to a B2-ordered single phase were designed and fabricated by melting route. The design concept of high entropy alloys is applied to engineering the transition metal sublattice of binary B2 aluminide. The equiatomic substitution of transition metal elements in the Ni sublattice of binary AlNi followed to produce Al(CoNi), Al(FeNi), Al(CoFe), Al(CoFeNi), Al(CoFeMnNi), and Al(CoCuFeMnNi) multicomponent alloys. CALculation of PHAse Diagrams (CALPHAD) approach was used to predict the phases in these alloys. X-ray diffraction and transmission electron microscopy were used to confirm the B2 ordering in the alloys. Thermal stability of the B2 phase in these alloys was demonstrated by prolonged heat treatments at 1373 K and 1073 K up to 200 h.

Highlights

High entropy alloys (HEAs) represent a new class of materials containing multiple principal elements in near-equiatomic compositions
The present study focuses on the design, synthesis, characterization, and phase stability of multicomponent B2 aluminides
High purity (>99.5%) elemental pieces/flakes/granules of Al, Co, Cu, Fe, Mn, Ni were used in required proportions to prepare the AlNi, Al(CoNi), Al(CoFe), Al(FeNi), Al(CoFeNi), Al(CoFeMnNi), and Al(CoCuFeMnNi) multicomponent B2 aluminides

Summary

Introduction

High entropy alloys (HEAs) represent a new class of materials containing multiple principal elements in (generally) near-equiatomic compositions. HEAs were reported to have fascinating properties such as superior strength–ductility trade-off [1,2], high thermal stability [3], corrosion resistance [4], wear resistance [5], enhanced resistance to oxidation [6], good hot deformation behavior [7], etc. HEAs were initially expected to form single-phase solid solutions due to the high configurational entropy caused by the presence of multiple elements [9]. The existence of a single-phase solid solution at room temperature was observed for the CoCrFeMnNi HEA system, known as the Cantor alloy [12]

Methods

Results

Conclusion