Microstructure and Mechanical Properties of Novel Lightweight TaNbVTi-Based Refractory High Entropy Alloys.

Ao Fu,Shenghang Xu,Yuxi Liu,Yuankui Cao

doi:10.3390/ma15010355

Abstract

A series of novel lightweight TaNbVTi-based refractory high entropy alloys (RHEA) were fabricated through ball-milling and spark plasma sintering (SPS). The reinforced phase of TiO precipitates were in-situ formed due to the introduction of Al2O3 ceramic particles. The RHEA with 15% Al2O3 exhibits a high compressive yield strength (1837 MPa) and a low density (7.75 g/cm3) with an adequate ductility retention. The yield strength and density are 32% higher and 15% lower, respectively, compared to the RHEA without Al2O3 addition. The specific yield strength (237 MPa cm3/g) of the RHEAs is much higher than that of other reported RHEAs, and is mainly ascribed to the introduction of high volume fraction of Al2O3 additives, resulting in solid solution strengthening and precipitation strengthening. Meanwhile, the ductile matrix is responsible for the good compressive plasticity.

Highlights

High entropy alloys (HEAs) are generally consisted of four or more principal elements in either equi-atomic or near equi-atomic composition, and tend to form simple solid solution structures, e.g., face-centered cubic, body-centered cubic and or hexagonal close-packed, instead of complex phases or intermetallic compounds [1,2]
HEAs have recently received much attention owing to their unprecedented promising properties, such as outstanding strength, excellent fracture toughness, remarkable wear and corrosion resistance, etc. [2,3,4,5,6]
The TaNbVTi-based refractory high entropy alloys (RHEA) were prepared by powder metallurgy (P/M) method

Summary

Introduction

High entropy alloys (HEAs) are generally consisted of four or more principal elements in either equi-atomic or near equi-atomic composition, and tend to form simple solid solution structures, e.g., face-centered cubic (fcc), body-centered cubic (bcc) and or hexagonal close-packed (hcp), instead of complex phases or intermetallic compounds [1,2]. Refractory high entropy alloys (RHEAs) consisted of refractory elements, such as W, Mo, Ta, Nb, V, Ti, Zr, etc., have attracted increasing attention by virtue of their superior mechanical properties at room and elevated temperature [8,9,10,11]. Their high density (up to 10–14 g/cm3) and consequent low specific strength restrict their engineering application. The density of the alloy decreased from 9.94 to 9.05 g/cm, and the specific yield strength increased from 93.56 to 203.43 MPa·cm3/g [16] The microstructural evolution and its effects on mechanical properties were analyzed

Experimental Procedures

Findings

TeMsteinthgod Method