Within the frames of the fluctuation model of deformation of a nonlinear locally inhomogeneous medium, we consider a model of genesis of micro-cracks during loading. To study the dynamics of accumulation of density of micro-cracks, we use the dimensionless instantaneous strain hardening modulus; this modulus depend on the critical index defined, in its turn, by statistic parameters of locally inhomogeneous medium. A direct observation of the process of micro-fracture of the hyper-modular chaotic composite material Al-SiC using the method of acoustic emission has proven the validity of the estimations obtained.