X rays are universally valued for their ability to penetrate opaque objects. It is only within the past few decades that their short wavelengths have also been exploited to provide 3D imaging of the objects' interiors with resolution well beyond that of light microscopy (LM) in a wide variety of applications. This article explores X-ray imaging as a quantitative sub-micron nanoscale microscopy technique, and specifically its emergent role within the context of the central microscopy laboratory.

For many years, a fundamental problem in contact mechanics, both tribology and indentation problems, has been the inability to see what is taking place—the buried-interface problem. Over the past few years, there have been developments whereby it has become possible to perform contact mechanics experiments in situ within a transmission electron microscope. These new experiments have been enabled by both the miniaturization of sensors and actuators and improvements in their mechanical stability and force sensitivity. New information is now becoming available about the nanoscale processes of sliding, wear, and tribochemical reactions, as well as microstructural evolution during nanoindentation such as dislocation bursts and phase transformations. This article provides an overview of some of these developments, in terms of both the advances in technical instrumentation and some of the novel scientific insights.