Mg-Al-Zn-Ca系マグネシウム合金の半凝固鍛造の成形可否の検討

抄録

Semi-solid forging is a forging method in which slurry in a semi-solid state is forged using a die to obtain a near-net-shape that is close to the finished product. Compared to casting and cold forging, semi-solid forging has the advantages of better dimensional accuracy and lower forming load. The objective of this study was to increase the strength of magnesium alloys, which are lightweight among practical metals and have excellent mechanical properties such as high specific strength and electromagnetic shielding properties. The molten metal was stirred during slow cooling to refine and spheronize the crystals, followed by semi-solid forging using a servo press. This resulted in an evaluation by a compression test in addition to verification of formability. The load-stroke diagram indicated that semi-solid forging was feasible for four materials under the experimental conditions. However, cracking and burring occurred under some conditions. Stress-strain diagrams from the compression tests showed that the ductility of AZX912 was improved by the semi-solid forging, while no difference was observed in AZX1312, AZX1712, and AZX2112 depending on the solid phase ratio．