Abstract
It is well known that many high performance sintered alloys have been produced by Metal Injection Molding (MIM) process so far. A Fe-Ni system is one of the objected alloys, and they are used for machine structural parts. Although assessment of the dynamic fracture properties such as fatigue strength is important to design a reliable sintered structual parts, there are few reports for the dynamic properties of MIM alloys even at the present time.
In this study, the behaviore of dynamic properties (impact and fatigue strength) for Fe-Ni (Fe-2, 4 and 7mass%Ni) alloys produced by MIM process has been investigated. Approximately 96% of theoretical density was obtained in all Fe-Ni alloys. Impact strength of MIM alloys was superior to that of the conventional P/M alloys, because the pore structure of the former was fine and spheroidized as compared to that of the latter. Fatigue strength was increased with increasing Ni content because of the solution strengthening and grain refining effects. Endurance ratio of MIM alloys was similar to that of the wrought alloys.
