Particle engulfment and pushing by solidifying interfaces. I. Ground experiments

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Physical metallurgy and materials science, 1998-06, Vol.29A (6), p.1691-1696A
• Main Authors: Juretzko, F R, Stefanescu, D M, Dhindaw, B K, Sen, S, Curreri, P A
• Format: Article
• Language: English
• ISSN: 1073-5623

Directional solidification experiments have been carried out to determine the pushing/engulfment transition for two different metal/particle systems. The systems chosen were aluminum/zirconia particles and zinc/zirconia particles. Pure metals (99.999% Al and 99.95% Zn) and spherical particles (5500 mu m in diameter) were used. The particles were nonreactive with the matrices within the temperature range of interest. The experiments were conducted so as to ensure a planar solid/liquid (SL) interface during solidification. Particle location before and after processing was evaluated by x-ray transmission microscopy (XTM) for the Al/ZrO sub 2 samples. All samples were characterized by optical metallography after processing. A clear methodology for the experiment evaluation was developed to unambiguously interpret the occurrence of the pushing/engulfment transition (PET). It was found that the critical velocity for engulfment ranges from 1.9-2.4 mu m/s for Al/ZrO sub 2 and from 1.9-2.9 mu m/s for Zn/ZrO sub 2 .