Prakt. Met. Sonderband 52 (2018) 127
MICROSTRUCTURAL CHARACTERISATION OF A HIGH
ENTROPY ALLOY
M. Speicher”, R. Scheck, D. Willer", J. Wagner?
1) Materials Testing Institute (MPA), University of Stuttgart, Stuttgart, Germany
2) previously Institute of Materials Science, University of Stuttgart, Stuttgart, Germany
_ ABSTRACT
Yoox ver | In this work the microstructure as well as the precipitation structure of a high entropy alloy
Al-Cu-Ni-Ti-V with an equiatomic composition (AI20Fe20Ni20Ti20V20 in at.%) was
investigated on several length scales. Different material states before and after heat
treatment were characterized by optical and scanning electron microscopy and 3D atom
probe tomography. In addition, the phases were identified by X-ray diffraction and the
mechanical properties were determined in the compression tests.
1. INTRODUCTION
rlyische High entropy alloys (HEA) is a quite novel group of metallic materials. These alloys consist
Ava of near-equiatomic concentrations of several metallic elements. They fundamentally differ
ss from conventional alloys, which commonly consist of a primary element with additions of
felfol alloying elements in order to achieve desired properties. This new concept of alloy design
with no base element opens up a huge multi-component space with significant
technological potential and poses challenging scientific questions. Due to the intrinsic and
specially emphasized microstructural properties of high entropy alloys, like high lattice
strains or locally strongly changing chemical potentials, one could use these properties to
echanisch ind develop a hydrogen resistant HEA. Hydrogen embrittlement (HE) is observed in a large
Co variety of metallic materials (i.e. Al, Ni, Fe and their alloys) and applications [1]. Since HE
Weg corresponds to decreasing fracture toughness, it is an important industrial and technical
er. De problem. Additionally, with the depletion of fossil fuels, hydrogen is believed to be a
It, ist fiir Mg- possible energy source in future. Thus, for the efficient and effective use of hydrogen, safe
> mechanische hydrogen storage and transportation, e.g. to and from hydrogen fuel cells or large-scale
sien sodas Production facilities will become necessary. To develop tailored materials for this purpose,
n Phasen und however, is still challenging, since the interactions of hydrogen with metals at different
time- and length scales are still not fully understood. Currently, there are only a few studies
en geal about the usage of HEA in hydrogen rich environments, most of them dealing with the
aratonsgerale ability of HEA to store hydrogen for future energy purposes [2-4].
uf kommen mit In this study the first results on the microstructure and mechanical properties of a Al-Cu-Ni-
Präparationen Ti-V alloy with an equiatomic composition (Al20Fe20Ni20Ti20V20 in at.%) are presented.
rerich. Beide The aim for the developing of this alloy is to design material resistant again the hydrogen
embrittlement.
Iremen, Leibniz
ingen, Struers
