PPBF-EB process of Al alloys and its phase trnsformation kinetics

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K03801
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 18020:Manufacturing and production engineering-related
• Research Institution: Tohoku University
• Principal Investigator: Aoyagi Kenta 東北大学, 金属材料研究所, 助教 (90636044)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: Additive Manufacturing / Al合金

Outline of Final Research Achievements

In order to realize the PBF-EB process for Al alloys, we conducted the analysis of smoke behavior for Al alloy powder, process optimization and fabrication of defect-less Al alloy by PBF-EB,investigation of the dependence of microstructure on the building conditions, the analysis of microstructural change behavior after solidified. It was revealed that when the cooling rate was increased, a region, where fine precipitates aggregated, was formed in a layered form perpendicular to the building direction.It was considered that a solute-concentrated region formed in the solid-liquid coexistence region near the bottom of the melt pool with small flow velocity, and at this region as a nucleation site, fine precipitates were formed.
In addition, the temperature history could be estimated from the building log data and microstructure change behavior after solidified could be explained by this estimated temperature history.

Free Research Field

材料加工、組織制御

Academic Significance and Societal Importance of the Research Achievements

本研究成果は、金属用3Dプリンタを用いてAl合金を造形する際に、形状だけでなく材料内部の組織を制御するための科学として重要性を持つ。例えば、急速凝固により、従来製法よりも過飽和にAlが固溶した晶出物が形成し、その後の時効で晶出物内部にAlが析出することを明らかにした。また、これまで実例のほぼない電子ビームを熱源に用いた金属用3Dプリンタで種々のAl合金を造形でき、レーザを熱源に用いた金属用3Dプリンタとは異なった組織を有し、造形時の温度履歴からその組織を推定できることを見出した。電子ビーム3DプリンタによるAl合金部材の製造のための基礎的知見として、実用及び社会的にもその意義は大きい。