Machine learning capabilities combined with

in-situ

TEM measurements on aluminum-carbon nanotube composites reveal a new deformation sequence of dislocation gliding and pinning

a quiescent period

and finally a sudden release of localized strain. We propose a plastic deformation mechanism operating with three essential distinguishing characteristics: correlation of spatially localized microstrustural defects on the scale of nanometers

barrier-activation process of shear stress loading giving rise to strain response

and transient response on the time scale of seconds. Implications regarding plasticity carriers known to operate in crystalline media and in amorphous solids such as metallic glasses are discussed.