Hydrogen trapping and permeability in carbon fiber reinforced aluminum alloys

Carbon fibers and aluminum-based alloys are the most common choice for today's advanced hydrogen storage solutions due to their lightweight. They also combine exceptional mechanical performance and resistance to most chemicals. However, carbon fibers alone are the primary cost driver for hydrogen storage systems and high-strength aluminum alloys suffer from hydrogen embrittlement. Therefore, alternative carbon fiber-reinforced aluminum alloys can be considered to optimize storage tank costs. But, the effect of adding of carbon fibers on hydrogen trapping in an aluminum-based matrix has not yet been understood. To elucidate this, in this study, the interaction between hydrogen and a carbon fiber-reinforced aluminum alloy was investigated by correlating nano/microstructure characterization, hydrogen mapping techniques, and high-pressure hydrogen permeation tests. It is suggested that carbon fiber-reinforced aluminum alloy has three additional hydrogen trap sites compared to the reported traps for the aluminum alloy. The results showed that hydrogen trapping at these traps reduces the hydrogen permeability of composite material compared to a monolithic aluminum alloy.