Abstract
Diffusion bonded alloy powders such as Fe-4 %Ni-0.5 %Mo-1.5 %Cu (AE) and Fe-1.75 %Ni-0.5 %Mo-1.5 %Cu (AB) are widely used for many PM components due to their high mechanical strength. This is primarily an effect of the unique heterogeneous microstructure with martensitic structure around pores that is created already after ordinary sintering, i.e. not sinter hardening. Consequently, these materials achieve much higher strength than the traditional Fe-Cu-C alloying system. These alloying systems also achieve higher densities in comparison to pre-alloyed powder due to their higher compressibility. On the other hand to increase the competitiveness of PM a leaner diffusion bonded alloy powder Fe-0.5 %Ni-0.5 %Mo (AQ) and some lean pre-alloyed powders have been developed. The as-sintered mechanical properties of them are not adequate in comparison with AE or AB. However, if the heat-treated properties of them are comparable to AE or AB, those leaner alloys would introduce as a more cost effective alternative. First, in order to clarify what the advantage or the disadvantage of AE, AB and AQ is, static and dynamic mechanical properties of them were compared in this study. Second, the mechanical properties of AQ were compared with properties obtained with the lean pre-alloyed materials Fe-0.85 %Mo (85Mo) and Fe-0.45 %Mo (45Mo) at different heat treatment conditions.
