INFLUENCES OF ALLOYING ELEMENTS Cu AND Ni ON SINTERING CHARACTERISTICS OF SHORT CAST IRON FIBRES

The law of influences of alloying elements copper and nickel contents on the sintering characteristics of short cast iron fibres sintered at 1100℃ was studied. Results have shown that in comparison with ironcopper powder compacts, short cast iron fibre-copper compacts obviously decrease maximum expansion rate and corresponding copper contents. The main reason of expansion consists in that the liquid phase riched in copper diffuses into austenite after copper melting and pores remain in situ and there is no clear flow of liquid phase along interface.Nickel obviously speeds up the densification of sintered compacts with short cast iron fibres, When nickel content is more than 4.5%, austenitic phase is presented in microstructure, uncontinuous network-shaped cementite is precipitated in the interface between austenites and pearlites, and widmanstatten carbides and free graphites are precipitated in austenitec grains. Therefore densification rate decreases and the ductility fracture mode changes into brittleness.