Experimental verification of velocity dependence of dynamic contact angle in high-speed shape-controlled single-crystallization technology of refractory alloys

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K20473
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0401:Materials engineering, chemical engineering, and related fields
• Research Institution: Tohoku University
• Principal Investigator: Murakami Rikito 東北大学, 金属材料研究所, 助教 (30963665)
• Project Period (FY): 2022-08-31 – 2024-03-31
• Keywords: マイクロ引下げ法 / 接触角 / Growth angle / メニスカス / 濡れ性 / 形状制御 / 合金線材

Outline of Final Research Achievements

The micro-pulling-down method in a low-wettability system (dewetting μ-PD method) is a recently developed high speed, shape controlling, surface tension based single crystal growth method that enables rapid wire production in a single process of difficult-to-machine materials previously thought to be impossible to machine.
Unlike conventional methods, this method exhibits features such as a positive dependence of crystal diameter on pulling rate, which was expected to be influenced by the rate dependence of the advancing contact angle. In this study, the influence of the advancing contact angle was confirmed by measuring the growth angle, and by comparing the deviation between the theoretical value and the value predicted from the crystal growth test, it was shown that the advancing contact angle and its velocity dependence varied depending on the system.

Free Research Field

結晶工学

Academic Significance and Societal Importance of the Research Achievements

濡れ性の低い系におけるマイクロ引下げ法（Dewetting μ-PD法）によれば、IrやRuといった融点が2,000℃を超える合金の単結晶長尺線材をシングルプロセスで製造することができる。工業的な水準として、線径0.8 mmに対して±10 μm以下の形状制御性が求められてきたが、Dewetting μ-PD法では従来の結晶育成法における形状制御の指針が適用できないことが課題であった。本研究によって、Growth angleと前進接触角の速度依存性を考慮することにより、目的の線径を得るための結晶育成条件の最適化を行うことが可能となった。