Abstract Cold spray is capable to additively manufacture oxide-free metallic parts in open air due to its low processing temperature. However, for metals with relatively high hardness such as Inconel 718 superalloy (IN718), it is still a big challenge to get dense deposits by using low-priced nitrogen gas. In this work, In-situ micro-forging (MF) was introduced to cold spray by mechanically mixing big-sized 410 stainless steel (410SS) particles into the IN718 powder so that the deposited IN718 layer can be hammered and plastically deformed by the MF particles during spraying and results in fully dense deposits. As 50 vol% MF particles were mixed into the IN718 powder, the porosity was decreased from 5.6% to 0.26%. Due to the low impact velocity, 410SS particles were not embedded into the IN718 deposits and the possible contamination was avoided. An oxide scale removal induced increment in deposition efficiency was detected for the first time. Due to the lower porosity and enhanced inter-particle bonding, a great improvement in ultimate strength from 96 to 464 MPa was achieved by the in-situ MF effect. After heat treated at 1200 °C for 6 h, the sample fractured at a high strength of 1089 MPa and revealed a ductile fracture manner.

中文翻译：

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原位微锻辅助冷喷涂增材制造的 Inconel 718 合金的沉积行为、微观结构和机械性能

摘要 冷喷涂由于其加工温度低，能够在露天环境中增材制造无氧化物金属零件。但是，对于Inconel 718高温合金（IN718）等硬度相对较高的金属，使用低价氮气获得致密沉积物仍然是一个很大的挑战。在这项工作中，通过将大尺寸的 410 不锈钢 (410SS) 颗粒机械混合到 IN718 粉末中，将原位微锻 (MF) 引入冷喷涂，使沉积的 IN718 层可以被 MF 锤击和塑性变形在喷涂过程中产生颗粒并导致完全致密的沉积物。由于将 50 vol% MF 颗粒混合到 IN718 粉末中，孔隙率从 5.6% 降低到 0.26%。由于冲击速度低，410SS 颗粒没有嵌入 IN718 沉积物中，避免了可能的污染。首次检测到氧化皮去除引起沉积效率增加。由于较低的孔隙率和增强的颗粒间结合，通过原位 MF 效应实现了极限强度从 96 MPa 大幅提高到 464 MPa。样品在 1200 ℃下热处理 6 h 后，在 1089 MPa 的高强度下断裂，并显示出韧性断裂方式。