To conclude our studies for the sintering in mixed powder compacts of Fe-Cu-C ternary system, the authors investigated the mechanical properties of Fe-(0- 10)%Cu-(0-1.0)%C ternary sintered compacts in relation to the addition of copper and graphite.
The results obtained were summarized as follows:
(1) The dividing ridge connecting the maximum points of hardness makes a line between the point of 4.0%Cu without graphite which corresponds to Fe-Cu binary eutectoid, and the point of 6.0%Cu with 1.0%C corresponding to Fe-Cu-C ternary eutectoid. The dividing ridge of tensile strength, however, is nearly perpendicular to the axis of copper content and passes the point of 4.0%Cu independent of graphite addition. On the other hand, the elongation becomes lower with increasing copper and graphite contents; the elongation of Fe-Cu-1.0%C ternary sintered compacts containing more than 6.5% Cu is less than 1.0%.
In order to produce a good quality of sintered copper steel, the proper compositions of copper and graphite are considered to be 0.51.0%C and 26.0%Cu, respectively.
(2) For the specimen of Fe-4.0% Cu-C ternary sintered compacts containing up to 1.0% C, a similar improvement of mechanical properties to the wrought copper steel was made due to the precipitation of e phase which occurs during annealing between 400'-500'C after being waterquenched from 910°C ×15 min.
