Effects of the structural state on the failure of magnesium-modified cast iron

Abstract

1. The structure of a fracture surface is affected by the shape, size, and distribution of the graphite grains. The failure rate is also controlled by the graphite inclusions. 2. The path of a crack is uniquely determined by the graphite inclusions and is independent of the form of loading for the pearlitic and bainite forms of matrix in grey and alloyed cast irons, and it is also independent of the failure conditions. 3. The total failure time is governed not only by the deformation characteristics but also by the relaxation ones. 4. The failure rate in the matrix is constant in these materials and is governed by the stress concentration around the graphite inclusions. 5. Mechanical hardening up to a critical value on the whole does not reduce the tendency to brittle failure but does reduce the relaxation time around the graphite inclusions.