Solid solution hardening in CrMnFeCoNi-based high entropy alloy systems studied by a combinatorial approach

Abstract

Solid solution hardening in high entropy alloys was studied for the Cantor alloy using diffusion couples and nanoindentation. We study a continuous variation of the alloying content and directly correlate the nanoindentation hardness to the local composition up to the phase boundary. The composition dependent hardness is analysed using the Labusch model and the more recent Varvenne model. The Labusch model has been fitted to experimental data and confirms Cr as the most potent strengthening element. For comparison of the experimental hardness and the predicted yield strength of the Varvenne model, a concentration-dependent strain-hardening factor is introduced to account for strain hardening during indentation, which leads to a very good agreement between experiment and model. A study of the input parameters of the Varvenne model, performed by atomistic computer simulations, shows no significant effect of fluctuations in the atomic size misfit volumes or in the local shear modulus to the computed yield strength. Graphic Abstract

A review on high-throughput development of high-entropy alloys by combinatorial methods

“…Thus, EDS analysis can often be carried out in parallel such that phase and composition can be resolved almost simultaneously. For experiments that include many phases and samples, there is a need to automate the phase analysis process to make the process more efficient [195,29] . Many groups have used high-throughput SXRD to rapidly identify phases in combinatorial material libraries [196] .…”

“…Many groups have used high-throughput SXRD to rapidly identify phases in combinatorial material libraries [196] . The majority of these studies used thin films produced by magnetron sputtering [29,195,197,198] . However, there are almost no studies of large bulk materials that used similar highthroughput methods for phase structure analysis.…”

“…Magnetron sputtering uses a magnetically confined plasma to accelerate positively charged ions toward a target material, leading to the sputtering of the target atoms onto a substrate to form a thin film with a thickness ranging from a few nanometers to a few microns [24] . A combinatorial materials library can be built by sputtering multiple elemental targets onto a single substrate [24][25][26][27][28][29] . The diffusion multiples method involves arranging different metals such that they are physically touching.…”

Solid solution hardening effects on structure evolution and mechanical properties of nanostructured binary and high entropy alloys after high pressure torsion

“…The Ni20 HEA still shows a large drop in hardness up to 900°C. A further decrease at higher temperatures is also not expected in this case, as the hardness of the Cantor alloy after 1150°C annealing is in the same hardness range [39].…”

Current trends in nanomechanical testing research

“…Because a statistical analysis does not always yield an unequivocal identification of the material phases, there is a growing trend of performing correlative analyses, which combine nanoindentation mapping with imaging of the sample surface using one or more analytical techniques [27-29, 32, 33]. Alternatively, numerical simulations can be used to inform the experiments and data analysis [32,34]. The most widely used imaging techniques are backscattered electron diffraction (EBSD) for mapping the crystallographic orientation and energy dispersive X-ray spectroscopy (EDX) for local chemical characterization [27-29, 32, 33].…”