Macrostructure and Mechanical Properties of AC4C Aluminum Alloy Cast with Mechanical Vibration

• Published in: Journal of Japan Foundry Engineering Society Vol. 81; no. 11; pp. 536 - 542
• Main Authors: Omura, Naoki, Murakami, Yuichiro, Li, Mingjun, Tamura, Takuya, Miwa, Kenji, Furukawa, Hideki, Harada, Masayuki
• Format: Journal Article
• Language: Japanese
• Published: Japan Foundry Engineering Society 25.11.2009
• Subjects: alloy; aluminum; casting defect; computed tomography; mechanical properties; mechanical vibration; metallic mold; refining; X-ray
• ISSN: 1342-0429; 2185-5374
• DOI: 10.11279/jfes.81.536

  Gravity die castings of AC4C aluminum alloy with mechanical vibration (0-120Hz) were conducted. Columnar rod specimens (25mmΦ × 210mmL) were cast to investigate the effects of vibration and mold temperature on macrostructure, casting defects, and mechanical properties of gravity die castings. The grain size of the columnar rod casts at the mold temperature of 663K decreased from 1500μm (0Hz) to 800μm (100Hz) with the imposition of mechanical vibration. But at the mold temperature of 633K, the grain size was independent of the vibration frequency, and was about 200-300μm. The casting defects at the middle area of the specimen decreased with mechanical vibration below 70Hz in frequency. But vibrations above 80Hz led to increase in casting defects. As a result, the mechanical properties of specimens cast with vibration of frequency 70Hz showed higher UTS (ultimate tensile strength) and elongation (150MPa and 5-6%) compared with the specimens cast at other vibration conditions. The specimens cast without vibration showed a relatively large change in UTS, covering about 40MPa, when the mold temperature varied from 633K to 663K. However, no difference in UTS could be found in specimens vibrated at 70Hz even when the mold temperature dropped extensively by about 60K.