Quantitative evaluation of dislocation density using minor-loop scaling relations

Relationships between minor hysteresis loops and dislocation density have been investigated at various temperatures from 10 to 600 K in polycrystalline nickel with tensile deformation. It was revealed that coefficients obtained from scaling relations between parameters of minor-loops are in linear proportion to stress at all measuring temperatures below its Curie temperature. Considering that dislocation density is generally in proportion to the square root of true stress, it is concluded that the coefficients are related with the square root of dislocation density. This method using minor hysteresis loops is useful for quantitative evaluation of dislocation density because of its very low measurement field.