Abstract
The influence of deformation sub-structure on tensile properties was investigated on pure aluminum (99.9%) having the deformation sub-structure of various sizes formed by varying the amount of tensile prestrain.
The results obtained are summarized as follows;
(1) When the angle of misorientation between sub-grains varies with the sub-grain size, the flow stress increases parabolically with the inverse square root of the sub-grain size; and so Petch's relation does not hold true.
(2) When the angle of misorientation between sub-grains is constant independently of sub-grain size, Petch's relation holds true between the flow stress and the sub-grain size.
(3) The flow stress σf is proportional to the product of the square root of misorientation α and the inverse square root of the sub-grain size t, as expressed by a linear equation
σf=σ0+KMα1/2t-1/2.
(4) The flow stress σf increases with increasing excess dislocation density Db. This relation can be expressed by a linear equation
σf=σ0+α'GbDb1/2
which is of the same form with that derived from the work-hardening theory.
(5) The tensile strength could be expressed by a linear function of the inverse square root of the sub-grain size.
