文献类型：期刊文献

英文题名：Strengthening and Deformation Mechanisms of Laser Additively Manufactured Ni 2 Cocrnb 0.2 V 0.2 Medium-Entropy Alloy: Cryogenic to Elevated Temperatures

作者：Wang, Fangping Huang, Fang Guo, Yaxiong Liu, Qibin Liao, Tianhai

第一作者：Wang, Fangping

机构：[1] College of Materials and Metallurgy, Guizhou University, Guiyang, 550025, China; [2] Guiyang Vocational and Technical College, Guiyang, 550081, China; [3] Guizhou Institute of Technology, Guiyang, 550003, China; [4] Key Laboratory for Modern Manufacturing Technology, Educational Ministry, Guiyang, 550025, China

第一机构：College of Materials and Metallurgy, Guizhou University, Guiyang, 550025, China

年份：2024

外文期刊名：SSRN

收录：EI(收录号：20240106648);Scopus(收录号：2-s2.0-85204369921)

语种：英文

外文关键词：3D printing - Chromium alloys - Cobalt alloys - Cryogenics - Ductility - Entropy - High-entropy alloys - Niobium alloys - Precipitation (chemical) - Stacking faults - Yield stress

摘要：To develop a medium-entropy alloy (MEA) with a high yield strength at temperatures ranging from cryogenic (-196 ℃) to elevated (800 ℃) temperatures, a strategy of nanoparticle precipitation strengthening while reducing the MEA stacking fault energy (SFE) is proposed. A novel Ni2CoCrNb0.2V0.2 MEA suitable for additive manufacturing (AM) was designed based on the first-principles calculations and the calculation of phase diagrams (CALPHAD) technique. Bulk MEA samples were printed using laser directed energy deposition (LDED) with a vibration field. The first-principles calculations indicated that V addition could reduce the SFE and stabilize the γ′′ strengthening phase. The aged MEA had excellent yield strengths of ～1398 MPa and ～751 MPa at -196 ℃ and 650 ℃, respectively. In particular, the specific strength of the MEA can reach 94.16 MPa g?1 cm?3 at 650 ℃, which was greater than those of Waspaloy, IN625 and IN939. Systematic investigations revealed that precipitation strengthening by the γ′′ phase and the increased lattice potential friction are the dominant strengthening mechanisms at cryogenic temperatures. The deformational mechanism transforms from stacking fault (SF), deformation twin (DT), and Lomer–Cottrell (L-C) lock synergy to slip-dominated plasticity when the tensile temperature increases from -196 ℃ to 800 ℃. This research provides new theoretical guidance for developing AM-ed MEAs with a ultrastrong combination of strength and ductility for extreme applications. ? 2024, The Authors. All rights reserved.