Understanding the effect of tailored heat treatment on Zr-modified Al7075 fabricated by laser powder bed fusion
(2025) Materials & Design — Vol. 258, n° 114553, p. 1-17 (2025)
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- Authors
Rodriguez-Barber, Ignacio 
Pérez Prado, María Teresa
- Abstract
- Despite high-strength aluminium alloys now being widely processed by laser powder bed fusion (L-PBF), a specifically designed heat treatment (HT) for L-PBF Al7075 has yet to be identified and the microstructural features responsible for strengthening remain to be fully understood. In this study, fully dense Al7075+1.8%Zr was processed without hot cracking. High temperature heat treatments between 350°C and 525°C were adopted, attaining the highest hardness (162HV) at 425°C followed by an artificial ageing (AA). This heat treatment produced a yield strength of 515 MPa and an elongation at fracture of 12%. To understand the effect of this tailored low-temperature HT, comparisons were made with a classical T6 HT (1 h at 470°C followed by AA). Transmission electron microscopy analyses revealed a higher volume fraction of Al3Zr L12 secondary precipitates with the 425°C HT than with the 470°C HT. These hardening precipitates were quantified as the main contributor to strengthening, accounting for 207 MPa. The 425°C HT prevented the over-ageing Zr precipitates generated by the 470°C HT, while inhibiting recrystallization. eta′ precipitates played a minor role in the tensile properties as they were nearly absent from the microstructure due to the excessive evaporation of Mg and Zn during L-PBF.
- Affiliations
IMDEA IMDEA Materials Institute Université Lille 1 Université Lille 1
Citations
Nothomb, N., Rodriguez-Barber, I., Avettand-Fénoël, M.-N., Pérez Prado, M. T., Marinova, M., & Simar, A. (2025). Understanding the effect of tailored heat treatment on Zr-modified Al7075 fabricated by laser powder bed fusion. Materials & Design, 258(114553), 1-17. https://doi.org/10.1016/j.matdes.2025.114553 (Original work published 2025)