The Microstructure and Properties of an Al-Mg-0.3Sc Alloy Deposited by Wire Arc Additive Manufacturing

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.

Properties of Al-6Mg-xSc (x = 0 to 0.6 wt.%) Alloy Subjected to Thermal Treatment: A Review

“…In some cases delamination tearing is also visible. Formation of coarse dendrites has been observed at the failure zone of the scandium free base alloy and the failure was of brittle nature [57]. The fractograph of Sc added alloys consist of higher quantity of dimples, which is indication that the tensile specimen failed in relatively a ductile mode under the accomplishment of tensile loading.…”

Влияние Структурной Гетерогенности На Коррозионное Поведение Алюминиевых Сплавов И Их Сварных Соединений

“…URL: http://www.totalmateria.com/Article75.htm) (см. [869]). Детальный анализ микроструктуры сварного шва в зоне HAZ, представленный на рис.…”

Review of Aluminum Alloy Development for Wire Arc Additive Manufacturing

“…For WAAM, Sc was of particular interest and added to various 5000-series alloys [ 168 , 169 , 170 ]. The rapid solidification in WAAM supersaturated the Sc addition leading to significant precipitation strengthening post-WAAM [ 171 ]. Zr is often used as a substitute due to the high cost of Sc.…”