Grain Refinement of Cast Materials and Clarification of the Refining Mechanism using Mold Vibration Method

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K05114
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26060:Metals production and resources production-related
• Research Institution: Kurume National College of Technology
• Principal Investigator: Kaoru Yamamoto 久留米工業高等専門学校, 材料システム工学科, 教授 (00325515)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 凝固 / 結晶粒微細化 / 振動 / Al合金 / 鋳造

Outline of Final Research Achievements

The grain refinement of Al cast alloy was investigated using a mold vibration method. It was found that the primary α of Al-Cu alloy and the primary Si of Al-Si alloy can be summarized by the excitation force, which is a function of the amplitude and frequency of the mold vibration, and the grain size decreases with increasing excitation force. From the water model experiments, it was clarified that a large amount of crystals are generated at the boundary between the surface of the molten metal and mold wall when the molten metal is vibrated, and these many fine crystals fill the inside of the mold.Eutectic cells in eutectic alloys can be also refined by the vibration, and the cell size decreases with increasing excitation force, however the eutectic lamellar spacing does not change.
Furthermore, it was cleared that the combination of the mold vibration and inoculation has the potential to refine the grain size to about 100μm.

Free Research Field

材料組織制御

Academic Significance and Societal Importance of the Research Achievements

鋳造材は他の加工法と比較して安価に製造できるが，鍛造や圧延などのその他の製造過程によって製造された製品と比較して結晶粒が粗大化し，機械的特性が劣るという欠点がある．本研究では，新しく考案した鋳型振動装置を用いて溶湯に機械振動を与え，容易に結晶粒を微細化する新しいプロセスを見いだした．本研究により鋳型振動装置を用いた鋳造材の結晶粒微細化機構を解明するとともに結晶粒微細化手法を確立した．