The effect of powder size on the mechanical and corrosion properties and the ignition temperature of WE43 alloy prepared by spark plasma sintering

Powder metallurgy is a powerful method for the preparation of materials with superior properties. This work aimed to investigate the effect of powder size on the microstructure, mechanical, and corrosion properties of advanced WE43 (Mg-4Y-3REE-Zr) alloy prepared by spark plasma sintering (SPS). At the same time, the effect of HF pre-treatment of the powder on the properties of final compacted products is studied. Smaller powder particles yielded microstructure with more interfaces formed by Y2O3, or MgF2 and YF3. These interfaces work as barriers against corrosion, which greatly improves corrosion resistance. The suggested pre-treatment of powder in HF further reduced the corrosion rate of the compacted materials. On the contrary, fragile interfaces of YF3 decreased mechanical properties as the crack primarily propagates through these interfaces. The original powder containing the mixture of all powder fractions exerted the best combination of mechanical properties. Powder size has also shown to affect ignition temperature. The highest ignition temperature was measured for the finest powder fraction.