Strong adhesion induced by liquid-like surface of metallic glasses

Self-healing with the capability to be self-adhesive, which can recover from physical damage, is essential for space applications. However, regulatable adhesion under extreme space conditions has only been realized in low-dimensional materials and still poses a challenge on the discovery of suitable materials. Under an ultrahigh vacuum of 10⁻⁷ Pa, we found a strong adhesion between bulk Cu₄₆Zr₄₆Al₈ metallic glasses with a maximum adhesion strength of 32.8 kPa, which is two orders of magnitude higher than that of the corresponding crystalline. This adhesion is suggested to be induced by a liquid-like layer on a bulk metallic glass surface, which has a high diffusion coefficient of 6.9 × 10⁻¹¹ m²⋅s⁻¹, even at a relatively low temperature of 263 K. By investigating the dynamics for this liquid-like layer, a special fractional Stokes–Einstein relationship was found. Inspired by this strong adhesion, metallic glasses can be proposed as one of the promising self-healing materials for future space applications.