Effect of multi-variant thermal treatment on microstructure evolution and mechanical properties of AlSi10Mg processed by direct metal laser sintering and casting

Abstract

This article presents a study on the influence of temperature and time of multi-variant heat treatment on the structure and properties of materials produced in direct metal laser sintering (DMLS) and casting technology. The materials were manufactured in the form of cuboidal elements with a cross-section of 1.5 mm x 15 mm and a length of 60 mm. The samples prepared in this way had a similar volume, but due to the production technology the metal crystallization took place at different rates and directions. In the cast, the direction of heat transfer was toward the mold, and the DMLS was directed locally layer by layer. The small thickness of the cast material allowed reaching conditions similar to the DMLS cooling process. Both DMLS and cast samples show similar mechanical properties (hardness) achieved after long ageing time, i.e., 16 h at 170 degrees C. The maximum hardness was observed for 8 h. In the DMLS samples, in contrast to cast samples, no lamellar precipitates of silicon were observed, which indicates their better resistance to cracking.