PARTICLE INTERACTION IN THE ATOMIZATION OF HIGH-SPEED STEEL

Liquid, solid, and semisolidified particles in an atomized metal-gas spray experience numerous collisions, which exert a strong influence on the end structure of the bulk of the resultant powder. Very fine, rapidly solidified particles colliding with larger drops act as foreign inner centers of solidification. Collisions between previously solidified particles and drops of smaller weight are accompanied by a sharp increase in cooling rate during solidification (to 106–107 deg C/sec) and the formation on the particles of shells with a very fine-columnar structure (without any visible-signs of primary carbide evolution).