Abstract
This study was undertaken to examine the influence of filling pore with copper on the fatigue strength of copper-infiltrated sintered iron compacts by means of microscopical observation of the aspects of its fatigue fracture under low and high cycles.
The following conclusions are obtained from the investigation.
1) The tensile strength of copper-infiltrated sintered iron compacts exhibits the same value irrespective of green porosity by filling pore with copper in the same sintering condition.
2) In copper-infiltrated sintered iron compacts, the inflection point of the S-N curve is not clearly observed, and the curve is similar to that in cast iron, and the fatigue strength for the time rises differently from S-N curve of sintered iron compacts.
3) The fatigue strength of copper-infiltrated sintered iron compacts is not influenced by the green porosity under low cycles.
Under high cycles, the fatigue strength of the test pieces with the green porosity of 15% has the same value, but for the specimens with the green porosity over 15%, it falls as well as the sintered iron compacts, due to the difference in the shape of infiltrated copper.
