抄録
A fractographic study has been made on the fatigue fracture behaviour of sintered carbon steels: The specimens containing 0.2, 0.4, and 0.8 mass% carbon were made from atomized iron powders of different particle size (+145, -145+250, and -250 mesh), and were tested by a reversed bending at 30 Hz.
Fatigue fracture of sintered steels took place by coalescence of propagating main crack and micro cracks nucleated on the pore surface in front of the main crack, by means of cyclic and monotonic fracture mode. Hence, in fracture surface, both cyclic and monotonic fracture appearance were observed in single area of local fracture.
The fractional area of cyclic fracture mode was estimated by the apparent porosity in projected fracture surface, PA. Therefore, PA gives a useful information on the fatigue fracture behaviour of sintered steels.
