焼結鉄における空孔組織と機械的強さとの関係について

抄録

Sintered iron compacts have many pores, which seem to reduce the mechanical properties of them. The pore structure is very complex, and its influences on the mechanical properties are also complicated.
Then, authors analyzed the pore structure, particularly size, shape, and distribution, quantitatively, and its effects on the mechanical properties were investigated.
The following conclusions are obtained:
1) The size of pore becomes large in proportion as the porosity increases, and in a case of the same porosity, the pore size becomes large as the particle size of iron powder is large.
The shape of pore becomes irregular in proportion as the porosity increases.
2) Tensile strength decreases with increasing porosity, but in a case of the same porosity, the strength is not much influenced with particle size of iron powder.
On the other hand, fatigue strength varies not only with the porosity but also the particle size. This is considered to be caused by the characteristics of the mechanism of fatigue fracture.