Effects of heat treatment on microstructures and properties of a heterostructured alloy with dissimilar components fabricated by WAAM  

作　　者：Ming-Cai Pan Jun-Qiang Xu Yong Peng Ning-Ning Liang Si Lan Qi Zhou Ke-Hong Wang 

机构地区：[1]School of Materials Science and Engineering,Nanjing University of Science and Technology,Nanjing 210094,China [2]Key Laboratory of Controlled Arc Intelligent Additive Manufacturing Technology,Nanjing 210094,China

出　　处：《Rare Metals》2024年第9期4441-4461,共21页稀有金属（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.52301050);the Young Elite Scientists Sponsorship Program by the China Association for Science and Technology(No.2022QNRC001;the China Postdoctoral Science Foundation(No.2023M741701)。

摘　　要：Heat treatment significantly influences homogeneous material microstructures and mechanical properties,which can be improved by an optimal heat treatment process.However,heat treatment application to heterogeneous materials presents significant challenges due to compositional and microstructural heterogeneities.Herein,a laminated heterostructured alloy comprising alternating316L stainless steel(SS)and 18Ni300 maraging steel(MS)layers fabricated using wire and arc additive manufacturing was investigated.A solution treatment was applied at900℃for 0.5 h.Subsequently,the solution-treated and asfabricated(AF)samples were aged at 500℃for 4 h;these samples were denoted SA and AT,respectively.The AT phase compositions and orientations were similar to those of AF.The SA 316L SS layer resembled that of AF,but the SA 18Ni300 MS layers exhibited a reduced austenite phase fraction and refined grain size,attributable to solid-state transformation.In the AT sample,aging induced the formation of nanoscale acicularωphase and ellipsoidal Ni_(3)Ti,Fe_(2)Mo,and X precipitates in the 18Ni300 MS layers.Conversely,the SA precipitates contained acicular Fe Ni_(2)and ellipsoidalω,Ni_(3)Ti,and X precipitates,and their fractions were lower than those in AT precipitates.The18Ni300 MS layer microhardness in the heat-treated samples increased due to nanoprecipitation,but the 316L SS layer microhardness resembled that of AF.The AT and SA ultimate tensile strengths increased to(1360±50)and(1473±41)MPa,respectively,attributable to precipitation strengthening.The SA 316L SS layer exhibited a high stress-induced martensite fraction,enhancing the ductility of heated samples.

关 键 词：Laminated heterostructured alloy Heat treatment Wire and arc additive manufacturing Microstructure Mechanical property 

分 类 号：TG156[金属学及工艺—热处理] TG142.1[金属学及工艺—金属学]