The influence of hardening of a material on processes of deformation and destruction of cylindrical rods at uniaxial tension and compression was investigated by method of computer modeling. The calculation is lead within the limits of model porous elastic-plastic environments. The criterion of destructions is the limiting size of intensity of plastic deformations. The destruction is considered as process of growth of microdefects under action formed during stretching pressure loading. As local criterion of destructions the limiting size of relative volume of emptiness serves. The decision of a problem is lead in full three-dimensional statement modified on the decision of dynamic problems by a method of final elements. Features of deformation of samples of various lengths are elicited at isotropic hardening.