Importance of Size-Distribution of Dispersed Particles in Evaluation of Yield Strength of Particle-Dispersion-Strengthened Ferritic Steel

摘要

Particle dispersion strengthening is an effective method for increasing the strength of metals. It is well known that the increment of yield strength by particle dispersion strengthening, ACT, is proportional to the reciprocal of particle spacing, lambda~(-1), and is described by the equation: DELTA sigma =beta Gb/lambda (G: Shear modulus, b: Burgers vector, P: constant). Generally, the lambda is estimated from mean size and volume fraction of the particles. However, the size of particles is widely distributed in real materials, and this gives significant influences on the estimation of lambda~(-1) Therefore, it is important to estimate the effective lambda considering size-distribution of particles in order to evaluate the particle dispersion strengthening. In this study, the effect of size-distribution on lambda was investigated in some model materials with different type of size-distribution of dispersed particles, and then the yield strength was evaluated, taking the particle size-distribution into account in the particle-dispersed real materials.