Dependence of Strain Hardening Index on the Degree of Strain and on Fulfillment of the Exponential Law of Hardening.

As a result of processing experimental data for structural, tool and austenite steels, copper, aluminum and their alloys by the digital computer ″Nairi″ it is found that for the major part of metals and alloys the value of strain hardening index n changes in the process of plastic strain. For metals and alloys whose process of plastic strain is not complicated by phase-structural transformations the value of n decreases with the growth in the degree of strain epsilon , reaching the constant value mainly when epsilon equals 0. 6. . . 0. 8. For alloys of phase-structural transformations in the process of plastic strain the value of n first increases with the epsilon growth and then decreases. The applicability of the power equation is confirmed for the description of experimental curves of hardening under compression, however, it is stated that the power law of hardening for many metals and alloys is of approximate character. A close relation between the flow stress delta //s and epsilon is observed, the coefficient of correlation equaling 0. 935. . . 0. 995.