This paper aims to introduce a novel concept of a double-wire feed (DWF) to alleviate heat accumulation and improve the cooling rate of the molten pool in gas tungsten arc (GTA)-based additive manufacturing (AM), in which the former wire is fed into the arc and the latter wire is melt by the molten pool.,The microstructure, phase composition and mechanical properties of 308 L stainless steel components built by single-wire feed (SWF) AM and DWF-AM are compared, and the differences are analyzed in detail.,The microstructures for both wire feeding modes include δ and γ phases. Compared with the SWF-AM, the sample fabricated in the DWF-AM exhibits finer microstructure, and the microstructure in the middle region is transformed from columnar grains to cellular grains. Microhardness of the sample produced in the DWF-AM is higher than the SWF-AM. In comparison to the SWF-AM, the tensile strength of the specimen fabricated using the DWF-AM reaches 571 MPa and increases by 16.14%.,This study proposes a novel concept of the DWF-AM to reduce heat accumulation as well as enhance the cooling rate of the molten pool, and improved mechanical properties of the 308 L stainless steel component are obtained.

中文翻译：

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双丝喂料GTA增材制造308L不锈钢的显微组织和力学性能

本文旨在介绍一种新的双丝送丝 (DWF) 概念，以减轻热量积累并提高基于气体钨极电弧 (GTA) 的增材制造 (AM) 中熔池的冷却速度，其中前丝被送入电弧，后丝被熔池熔化。,比较了单丝送丝 (SWF) AM 和 DWF-AM 构建的 308 L 不锈钢部件的组织、相组成和机械性能，并比较了详细分析了差异。两种送丝模式的微观结构包括δ和γ相。与 SWF-AM 相比，DWF-AM 制备的样品显示出更精细的微观结构，中间区域的微观结构由柱状晶粒转变为蜂窝状晶粒。在 DWF-AM 中生产的样品的显微硬度高于 SWF-AM。