NONEQUILIBRIUM SOLIDIFICATION OF HIGH-ALLOY LEDEBURITIC TYPE STEEL

The results of the research work concerning the rapid solidification o f undercooled liquid droplets into small powder particles are presente d. The iron base ledeburitic type alloy with 2.3% C, 4% Cr, 2% W, 7-8% V, 10-11% Co, 8% Mo chemical composition has been subjected to the ex perimental evaluation. Hypoeutectic solidification mechanism has been determined in the specimen obtained by 10 K.min(-1) cooling rate and a lso in RS powder with a particle size more than 100 mu m. With the inc rease in cooling fate represented by a decrease in powder size, the ch ange in the mentioned mechanism to the hypereutectic one has been dete rmined. As such, the microstructure of a material is characterized by occurrence of small primary carbides in the centres of eutectic coloni es. The changes in phase composition as a function of powder particle size have been also found in RS material.