Achieving improved mechanical performance in aluminum matrix composites with rebar-reinforced concrete-inspired structures
Chenwei Shao, Huicong Chen, Yu Zou
Abstract
The strength of aluminum matrix composites (AMCs) often suffers from degradation at elevated temperatures, rendering them generally unsuitable for use in high-temperature environments. Inspired by ubiquitous rebar steel-reinforced concrete (RC) structures, we develop a series of RC-like AMCs by integrating the additive manufacturing and micro-casting methods. Such RC-AMC, with a high volume fraction of thermotolerant particulate reinforcements, effectively mitigate the strength degradation up to 500 °C. Through structural optimization, we demonstrate that such RC-AMCs achieve extraordinarily high compressive yield strength (up to 938 MPa) and specific strength (up to 235 kN·m/kg) at 400 °C — among the highest reported values for all the aluminum-based alloys and composites. The enhanced resistance to high-temperature softening in RC-AMCs is associated with abnormal thermal twinning in Al3Ti when the temperature increases. This design strategy, combining anomalous temperature-dependent deformation behavior and multiscale reinforcing architectures, offers a pathway toward structure-material integrated manufacturing for a wide range of engineering alloys and composites. Inspired by rebar steel-reinforced concrete (RC) structures used in buildings, aluminum matrix composites are designed which achieve nearly 1 GPa in yield strength and specific strength of (235 kN·m/kg) at 400 °C.