X-Ray Investigation on the Deformation of Inhomogeneous Metallic Materials

In a series of studies on the strength of inhomogeneous metallic materials, the authors have conducted an investigation on the macroscopic and X-ray elastic modulus of cast iron, and reported the experimental results in the previous papers. It has been suggested that the shape of graphite has little influence on the value of X-ray elastic modulus, but that the value of macroscopic elastic modulus is remarkably varied with the change in its shape.It is very interesting and significant to predict, from the known elastic moduli of component materials, the macroscopic and X-ray elastic modulus of inhomogeneous metallic materials, such as cast iron, powder metallurgy products and two phases alloys.In this paper report is made of the analytical treatment concerning the elastic modulus for inhomogeneous metallic materials which was carried out, using the simple mechanical models, and the calculated results are presented with reference to the experimental results obtained with cast iron.It is assumed that aninhomogeneous metallic material is composed of the cube-shaped unit structures, and that the unit structure contains a particle of B-phase floated in the matrix of A-phase. This unit structure is divided into two columns, one of which is composed of only A-phase and the other is composed of A- and B-phase. The condition of constant stress or constant strain is supposed as combining these two columns. Furthermore, the latter column is sub-divided into two parts, one of which consists of A-phase and the other B-phase, and the condition of constant stress or constant strain is also assumed as bond between these two parts.The analytical calculation of cast iron has been made assuming that the graphite particle is cube-shaped in spheroidal graphite cast iron, and plate-shaped in flake graphite cast iron, and that the value of elastic modulus is zero for the graphite particle. Good correlation is obtained between the analytical and the experimental results of these two sorts of cast iron.This analytical treatment is considered to be applicable also to powder metallurgy products, two phases alloys such as (α+β) brass, and so on.