The purpose of the present work is to investigate the effect of heat treatment on duplex powder preforms with liquid phase sintering For such a study, 4607 alloy steel powder with the separate addition of some clifferent brazing alloy powders were prepared as well as NC 100.24 iron powder. Some cylindrical duplex preform samples were produced by suitable compaction and sintering for different times. NC 100.24 iron powder was invaribly located in the core,whilst the sheath material was one of the alloy steel prepared with and without the additives. The specimens were then properly heat treated to record its effect on hardness values. Crushing tests and microhardness tests were performed across the material transition zone. The results were discussed in terms of micro—structures examination.