The Microstructure and Properties of an Al-Mg-0.3Sc Alloy Deposited by Wire Arc Additive Manufacturing
Open Access
- 28 February 2020
- Vol. 10 (3), 320
- https://doi.org/10.3390/met10030320
Abstract
Al-Mg alloys can reach medium strength without a solid solution and quenching treatment, thereby avoiding product distortion caused by quenching, which has attracted the attention of wire arc additive manufacturing (WAAM) researchers. However, the mechanical properties of the WAAM Al-Mg alloy deposits obtained so far are poor. Herein, we describe the preparation of Al-Mg-0.3Sc alloy deposits by WAAM and detail the pores, microstructure, and mechanical properties of the alloy produced in this manner. The results showed that the number and sizes of the pores in WAAM Al-Mg-0.3Sc alloy deposits were equivalent to those in Al-Mg alloy deposits without Sc. The rapid cooling characteristics of the WAAM process make the precipitation morphology, size, and distribution of the primary and secondary Al3Sc phases unique and effectively improve the mechanical properties of the deposit. A primary Al3Sc phase less than 3 μm in size was found to precipitate from the WAAM Al-Mg-0.3Sc alloy deposits. The primary Al3Sc phase refines grains, changes the segregated β(Mg2Al3) phase morphology, and ensures that the mechanical properties of horizontal and vertical samples of the deposits are uniform. After heat treatment at 350 °C for 1 h, the WAAM Al-Mg-0.3Sc alloy deposits precipitated a secondary Al3Sc phase, which was spherical (diameter about 20 nm) and had high dispersity. This phase blocks dislocations and subgrain boundaries, causes a noticeable strengthening effect, and further improves the mechanical properties of the deposits, up to a horizontal samples tensile strength of 415 MPa, a yield strength of 279 MPa, and an elongation of 18.5%, a vertical samples tensile strength of 411 MPa, a yield strength of 279 MPa, and an elongation of 14.5%. This Al-Mg-Sc alloy is expected to be widely used in the WAAM field.Keywords
This publication has 15 references indexed in Scilit:
- Wire + Arc Additive ManufacturingMaterials Science and Technology, 2016
- The strengthening effect of inter-layer cold working and post-deposition heat treatment on the additively manufactured Al–6.3Cu alloyMaterials Science and Engineering: A, 2016
- A comparative study of additive manufacturing techniques: Residual stress and microstructural analysis of CLAD and WAAM printed Ti–6Al–4V componentsMaterials & Design, 2016
- Hydrogen-induced gas porosity formation in Al–4.5 wt% Cu–1.4 wt% Mg alloyJournal of Materials Science, 2013
- Evolution of the structure and phase composition of rapidly solidified Al-Mg-Mn-Sc-Zr alloys during deformation in a bridgman anvilRussian Metallurgy (Metally), 2010
- Criteria for developing castable, creep-resistant aluminum-based alloys – A reviewZeitschrift für Metallkunde, 2006
- Coarsening kinetics of nanoscale Al3Sc precipitates in an Al–Mg–Sc alloyActa Materialia, 2005
- Nanostructural evolution of Al3Sc precipitates in an Al-Sc-Mg alloy by three‐dimensional atom probe microscopySurface and Interface Analysis, 2004
- The effect of cooling rate on the morphology of primary Al3Sc intermetallic particles in Al–Sc alloysActa Materialia, 2001
- Effect of Scandium on Recrystallization of Aluminum and its AlloysMaterials Science Forum, 2000