Journal of the Japan Society of Powder and Powder Metallurgy

Pure magnesium powders added 0.50 g of stearic acid as process control agent (PCA) were mechanically milled (MMed) 24 hours using a vibration ball mill. MMed powders were consolidated into bulk materials by spark plasma sintering (SPS). Changes in hardness, solid-state reactions, bulk density and thickness of the SPS materials have been examined by hardness measurements, an X-ray diffraction, measurements of weight, diameter, height and vernier caliper, respectively. The Vickers hardness of the SPS material decreased with increasing sintering temperature. A minimum hardness value of the SPS material was 19 HV. No effect of sintering pressure on thickness of the SPS materials was observed. Formation of MgH₂ by solid-state reaction during the SPS process was observed for the SPS materials. The sintering temperature contributed to the expansion of the SPS materials than the sintering pressure.

View full abstract

Show abstractHide abstract

In this study, we attempted to fabricate specimens with AlSi10Mg alloy powder by using laser directed energy deposition (DED-LB). Single- and multi-beads (plane) were fabricated with varying DED-LB process conditions, and the bead shapes were measured. Notably, the shapes significantly changed depending on the process conditions. Based on the results, appropriate DED-LB process conditions were selected, under which a smooth plane could be fabricated. Fabricating under the appropriate process conditions, AlSi10Mg DED-LB specimens with a high relative density of greater than 99.8% were obtained. Then, DED-LB specimens with a block shape were fabricated using different scanning patterns (XX and XY patterns) under the appropriate process conditions, and their microstructures and mechanical properties were investigated. The density and microstructural morphology of the DED-LB specimens changed depending on the scanning patterns. The DED-LB specimens fabricated using the XY scanning pattern, in which the scanning direction was changed for each layer, exhibited superior strength and ductility. This was attributed to the differences in relative density and microstructures of the specimens.

View full abstract

Download PDF (12296K)

Register with J-STAGE for free!