The effect of annealing on the tribological and corrosion properties of Al-12Si samples produced by selective laser melting (SLM) is evaluated via sliding and fretting wear tests and weight loss experiments and compared to the corresponding material processed by conventional casting. Sliding wear shows that the as-prepared SLM material has the least wear rate compared to the cast and heat-treated SLM samples with abrasive wear as the major wear mechanism along with oxidation. Similar trend has also been observed for the fretting wear experiments, where the as-prepared SLM sample displays the minimum wear loss. On the other hand, the acidic corrosion behavior of the as-prepared SLM material as well as of the cast samples is similar and the corrosion rate is accelerated by increasing the heat treatment temperature. This behavior is due to the microstructural changes induced by the heat treatment, where the continuous network of Si characterizing the as-prepared SLM sample transforms to isolated Si particles in the heat-treated SLM specimens. This shows that both the wear and corrosion behaviors are strongly associated with the change in microstructure of the SLM samples due to the heat-treatment process, where the size of the hard Si particles increases, and their density decreases with increasing annealing temperature.
Graphene
aerogel (GA) has attracted great attention due to its
unique properties, such as ultralow density, superelasticity, and
multifunctionality. However, it is a great challenge to develop superelastic
and fatigue-resistant GA (SFGA) with ultralow density because it is
generally contradictory to improve the mechanical properties with
reducing density of GA. Herein, we report a simple and efficient approach
to prepare ultralight SFGA templated by graphene oxide liquid crystal
(GOLC) stabilized air bubbles. The thus-prepared ultralight SFGA (∼2
mg cm–3) exhibits superelasticity (rapid recovery
from >99% compression) and unprecedented fatigue-resistant performance
(maintaining shape integrity after 106 compressive cycles
at 70% strain and 5 Hz). The ultralow density and excellent dynamic
mechanical properties of SFGA are mainly associated with the “volume
exclusion effect” of the air bubbles as well as the highly
ordered, closely packed, and uniform porous structure of the resultant
GA, respectively. This study provides a green and facile strategy
for preparing high-performance ultralight SFGA, which has great potential
in various applications, including ultrafast dynamic pressure sensors,
soft robot, and flexible devices.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.