Structures appearing in roughened steel surfaces obteined by self-dewetting with electrons

U. CROSSA ARCHIOPOLI; N. MINGOLO; O.E. MARTÍNEZ

METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE

ASM

Lugar: New York; Año: 2005 vol. 36 p. 999 - 1006

1073-5623

Heating and fast cooling of steel surfaces by means of a pulsed electron gun gives rise to peculiar structures characterized by a roughened surface due to spinodal self-dewetting and an intermediate region described as a heat-affected zone. In this work, numerical simulations of the heating of a steel surface by means of a pulsed electron gun are performed and contrasted with the experiments. The predictions of the depth of the melt pool and time elapsed above critical temperatures are used to interpret the experimental results. The combination of micrographs, cross sections, and numerical simulations allowed us to conclude that the instabilities giving rise to the dewetting structure are not related to vapor ejection. It is also concluded that the onset of the instability is a very fast process (on the order of at most a few microseconds), yielding a dewetting process that evolves in the entire melted pool, and that the spatial pattern scales with time elapsed above the melting temperature and the pool depth. The heat-affected zone (intermediate region) can now be understood to be where a solid-solid transformation occurs.