Direct imaging of short-range order and its impact on deformation in Ti-6Al.

Chemical short-range order (SRO) within a nominally single-phase solid solution is known to affect the mechanical properties of alloys. While SRO has been indirectly related to deformation, direct observation of the SRO domain structure, and its effects on deformation mechanisms at the nanoscale, has remained elusive. Here, we report the direct observation of SRO in relation to deformation using energy-filtered imaging in a transmission electron microscope (TEM).

Mechanical Enhancement of Bioinspired Polydopamine Nanocoatings.

Inspired by the catechol and amine-rich adhesive proteins of mussels, polydopamine (pDA) has become one of the most widely employed methods for functionalizing material surfaces, powered in part by the versatility and simplicity of pDA film deposition that takes place spontaneously on objects immersed in an alkaline aqueous solution of dopamine monomer. Despite the widespread adoption of pDA as a multifunctional coating for surface modification, it exhibits poor mechanical performance. Attempts to modify the physical properties of pDA by incorporation of oxidizing agents, cross-linkers, or carbonization of the films at ultrahigh temperatures have been reported; however, improving mechanical properties with mild post-treatments without sacrificing the functionality and versatility of pDA remains a challenge.

Assessment of lamellar level properties in mouse bone utilizing a novel spherical nanoindentation data analysis method.

In this work, we demonstrate the viability of using our recently developed data analysis procedures for spherical nanoindentation in conjunction with Raman spectroscopy for studying lamellar-level correlations between the local composition and local mechanical properties in mouse bone. Our methodologies allow us to convert the raw load-displacement datasets to much more meaningful indentation stress-strain curves that accurately capture the loading and unloading elastic moduli, the indentation yield points, as well as the post-yield characteristics in the tested samples. Using samples of two different inbred mouse strains, A/J and C57BL/6J (B6), we successfully demonstrate the correlations between the mechanical information obtained from spherical nanoindentation measurements to the local composition measured using Raman spectroscopy.