Abstract

Despite showing considerable potential, wire arc additive manufacturing (WAAM) has been limited to producing Al–Mg alloys. As the addition of Sc can improve the mechanical properties of Al–Mg alloys, in this study, Al–Mg–Sc alloy deposits with different Sc contents were prepared by a WAAM process. The porosity, microstructure, and mechanical properties of the deposits were studied. At Sc contents less than 0.15%, Sc was completely dissolved in the Al matrix without grain refinement, and the mechanical properties were slightly improved. At a Sc content of 0.3%, the primary Al₃Sc phase precipitated out of the as-deposited body, resulting in an abrupt change in the microstructure, significant grain refinement, significantly increased tensile strength and yield strength, with a tensile strength, yield strength, and elongation of 372 MPa, 270 MPa, and 22.5%, respectively. Following heat treatment at 350 °C for 1 h, the grain boundaries were refined and the secondary Al₃Sc phase was precipitated. Furthermore, the tensile strength and yield strength were significantly increased to 415 MPa and 279 MPa, respectively, and elongation decreased to 18.5%. At a Sc content of 0.45%, due to the aggregated precipitated phase, the coarsened grain boundaries and the limited solid solution amount of Sc in the α(Al) matrix (~ 0.25%), the mechanical properties were not further improved compared with the deposit with Sc content of 0.3%. Thus, based on economic considerations, the optimal Sc content was 0.3%. Owing to their enhanced mechanical properties, WAAM-produced Al–Mg–Sc alloys are expected to have a wide range of applications in aviation, aerospace.

Graphic Abstract

中文翻译：

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Sc含量对电弧增材沉积Al-Mg-Sc合金组织和性能的影响

摘要

尽管显示出巨大的潜力，但电弧增材制造（WAAM）仅限于生产Al-Mg合金。由于添加Sc可以改善Al-Mg合金的机械性能，因此在本研究中，通过WAAM工艺制备了具有不同Sc含量的Al-Mg-Sc合金镀层。研究了沉积物的孔隙率，微观结构和力学性能。当Sc含量小于0.15％时，Sc完全溶解在Al基体中而没有细化晶粒，并且机械性能略有改善。Sc含量为0.3％时，原始Al ₃Sc相从沉积物中沉淀出来，导致组织的突然变化，明显的晶粒细化，抗拉强度和屈服强度显着提高，抗拉强度，屈服强度和伸长率分别为372 MPa，270 MPa和分别为22.5％。在350°C下热处理1小时后，细化了晶界并形成了二次Al ₃Sc相沉淀。此外，抗拉强度和屈服强度分别显着增加至415 MPa和279 MPa，而伸长率降低至18.5％。在0.45％的Sc含量下，由于沉淀相的聚集，晶粒晶界的粗化以及在α（Al）基体中Sc的固溶量有限（〜0.25％），机械性能没有进一步提高。 Sc含量为0.3％的矿床。因此，基于经济考虑，最佳Sc含量为0.3％。由于WAAM生产的Al–Mg–Sc合金具有增强的机械性能，因此有望在航空，航天中得到广泛的应用。

图形摘要