In the past decade, nanomechanical techniques have become ubiquitous for mechanical measurement concurrently with the discovery of high-entropy alloys (HEAs). Different from large-scale testing, small-scale measurements offer quantitative details about mechanical behavior of materials at the micro/nanoscale, presenting new opportunities to probe fundamental nature of HEAs. This article will review the literature on using versatile nanomechanical tools for HEA studies, including nanoindentation, microcompression, high-temperature deformation, fracture measurement, and in situ electron microscopy. With these approaches, many interesting phenomena and properties of HEAs have been unveiled, for example, properties about incipient plasticity, strain-rate sensitivity, creep, diffusion, size-dependent strength, and fracture, which are difficult, or impossible, to be measured in macroscopic experiments. Despite current literature only focusing on a few HEA compositions and several methods, as nanomechanics and HEAs are developing rapidly, a new avenue of research is to be exploited. The article concludes with perspectives about future directions in this field.

A microcompressor is a precision mechanical device that flattens and immobilizes living cells and small organisms for optical microscopy, allowing enhanced visualization of sub-cellular structures and organelles. We have developed an easily fabricated device, which can be equipped with microfluidics, permitting the addition of media or chemicals during observation. This device can be used on both upright and inverted microscopes. The apparatus permits micrometer precision flattening for nondestructive immobilization of specimens as small as a bacterium, while also accommodating larger specimens, such as Caenorhabditis elegans, for long-term observations. The compressor mount is removable and allows easy specimen addition and recovery for later observation. Several customized specimen beds can be incorporated into the base. To demonstrate the capabilities of the device, we have imaged numerous cellular events in several protozoan species, in yeast cells, and in Drosophila melanogaster embryos. We have been able to document previously unreported events, and also perform photobleaching experiments, in conjugating Tetrahymena thermophila.