MM-SPSプロセスで作製した純マグネシウムの硬さに及ぼす焼結保持時間の影響

Abstract

Pure magnesium (Mg) powders together with different amounts of process control agent (PCA) were mechanically milled (MMed) using a vibration ball mill. Stearic acid was used as process control agent (PCA) for the mechanical milling (MM) process. The MMed powders were consolidated into bulk materials by the spark plasma sintering (SPS). Changes in hardness and solid-state reactions of the SPS materials have been examined by hardness measurements and an X-ray diffraction (XRD), respectively. A maximum hardness value of 102 HV obtained in the SPS materials fabricated from MMed 24 h powders with PCA1.50 g at sintering temperature of 823 K for 60 min. Formation of MgO by solid-state reaction was observed for the SPS materials consolidated from MMed 24 h powders with PCA1.00 g and 1.50 g. The amount of MgO formation increased with increasing sintering time. No correlation was observed between MgO formation and hardness. The Vickers hardness of the SPS materials improved by increasing sintering temperature. However, no significant change in hardness and constituent phases was observed with increasing sintering time. Pure Mg of hardness can be improved by MM-SPS process.