中性子を用いて合金の強化挙動を発見(Scientists use neutrons to discover strengthening behavior in alloys)

2023-01-18 オークリッジ国立研究所(ORNL)

＜関連情報＞

• https://phys.org/news/2023-01-scientists-neutrons-behavior-alloys.html
• https://www.sciencedirect.com/science/article/abs/pii/S1359645422009326?via%3Dihub

積層造形されたAlCuMnZr合金のクリープ変形時の荷重シャッフリング Load shuffling during creep deformation of an additively manufactured AlCuMnZr alloy

Richard A.Michi,Sumit Bahl,Christopher M.Fancher,Kevin Sisco,Lawrence F.Allard,Ke An,Dunji Yu,Ryan R.Dehoff,Alex Plotkowski,Amit Shyam
Acta Materialia  Available online: 26 November 2022
DOI:https://doi.org/10.1016/j.actamat.2022.118557

Abstract

The high-temperature deformation behavior of an additively manufactured Al-Cu-Mn-Zr alloy is evaluated in the as-fabricated and heat-treated states using traditional ex-situ and in-situ neutron diffraction creep experiments performed at 300 °C. The dominant reinforcement phase in the alloy, θ-Al₂Cu, despite its high volume fraction of ∼10%, does not provide load transfer strengthening during creep deformation. Instead, the lattice strain evolution suggests a new mechanism we term “load shuffling” wherein the initial load is transferred away from precipitate-free zones along the grain boundaries where most of the θ-Al₂Cu particles are located to precipitate-strengthened grain interiors. Notwithstanding the lack of load transfer strengthening, the as-fabricated AM Al-Cu-Mn-Zr alloy still possesses improved creep resistance at 300 °C relative to a cast alloy with similar composition. The proposed load shuffling mechanism explains the lack of observed L1₂-Al₃Zr strengthening at 300 °C and helps identify several strategies for improvement of elevated-temperature mechanical response of AM Al alloys.