By introducing nanoscale disordered interfaces into the ordered superlattice grains can achieved a combination of ultra-high strength and excellent ductility in NiAl-type high-temperature alloys, but limited by the complex preparation process. In the present work, a Ni(Al, Ti)-type multicomponent alloy of NiCoFeAlTiB was successfully fabricated using laser metal deposition (LMD) technique. The microstructural evolution, tensile properties and strengthening mechanism were investigated. Microstructural and phase analyses of the sample reveale the presence of dendritic γ + γ′ phases, γ′ envelopes and interdendritic γ + γ′ phases in the alloy. The LMD prepared NiCoFeAlTiB alloy exhibits superior mechanical property at both room temperature and elevated temperature. Compared to NiAl-type intermetallic alloys, the alloy exhibited excellent strength-ductility synergy at room temperature. In addition, the alloy's yield strength rises as temperature rises from 298 K to 973 K, reaching a maximum value of 1043 MPa at 973 K. The strength of the prepared NiCoFeAlTiB alloy is mainly contributed by lattice friction strengthening, solid solution strengthening, precipitation strengthening and the inherent yield strength of γ′ envelopes with precipitation strengthening, and the inherent yield strength is the key factor. This work provides insight into the preparation of Ni(Al, Ti)-type multicomponent alloy with superior mechanical property at both room temperature and elevated temperature by LMD.

中文翻译：

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激光熔化沉积优异力学性能Ni3(Al,Ti)型多元合金的显微组织演变及强度机制

通过在有序超晶格晶粒中引入纳米级无序界面，可以实现NiAl型高温合金超高强度和优异延展性的结合，但受限于复杂的制备工艺。在目前的工作中，采用激光金属沉积（LMD）技术成功制备了 NiCoFeAlTiB 的 Ni（Al，Ti）型多元合金。研究了微观结构演变、拉伸性能和强化机制。样品的微观结构和相分析表明合金中存在枝晶 γ + γ′ 相、γ′ 包络层和枝晶间 γ + γ′ 相。LMD制备的NiCoFeAlTiB合金在室温和高温下均表现出优异的机械性能。与NiAl型金属间合金相比，该合金在室温下表现出优异的强塑协同效应。此外，合金的屈服强度随着温度从298 K升高到973 K而升高，在973 K时达到最大值1043 MPa。所制备的NiCoFeAlTiB合金的强度主要由晶格摩擦强化、固溶强化、沉淀强化贡献。以及析出强化γ′包络线的固有屈服强度，而固有屈服强度是关键因素。这项工作为通过 LMD 制备在室温和高温下均具有优异机械性能的 Ni(Al, Ti) 型多元合金提供了见解。