Quasicrystal synthesis by shock compression

Abstract

Quasicrystals are of interest because of their unique nonperiodic structures and physical properties. Motivated by naturally occurring icosahedral AlCuFe- and decagonal AlNiFe-phases hosted in a shocked meteorite, different laboratories have undertaken a series of shock recovery experiments to understand their formation mechanism. Shock experiments generate a complex series of processes and conditions, including a near-instantaneous excursion to high pressure and high temperature, large shear stresses, local melting, rapid decompression, fast quenching and post-shock annealing. This highly dynamic scenario offers a very useful but imperfect tool for exploring the stability of novel alloys, such as quasicrystals. So far, all the shock-synthesized quasicrystals differ considerably in composition from any thermodynamically stable or metastable quasicrystals synthesized by metallurgical techniques at low pressure, leaving plenty of questions to be answered about their formation conditions and their nucleation and growth mechanisms occurring during shock experiments. In this Perspective, we summarize the previous studies of shock-synthesized quasicrystals and discuss the advantages and difficulties caused by the experimental complexity. We also propose a few directions for future experiments to better control the shock conditions and understand the properties of quasicrystals. Shock compression is a highly dynamic, useful tool for exploring the stability of novel alloys such as quasicrystals, but their formation conditions and the nucleation-growth mechanisms occurring during shock experiments remain largely elusive. Here, the authors provide a summary of quasicrystal shock-syntheses and discuss the advantages and difficulties caused by the experimental complexity.