Enhancement of Strength–Ductility Balance of the Laser Melting Deposited 12CrNi2 Alloy Steel Via Multi-step Quenching Treatment  

作　　者：Wei Zhang Zhi-Hong Dong Hong-Wei Kang Chen Yang Yu-Jiang Xie Mohamad Ebrahimnia Xiao Peng 

机构地区：[1]School of Materials Science and Engineering,University of Science and Technology of China,Hefei 230000,China [2]Shi-Changxu Innovation Center for Advanced Materials,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China [3]Zhejiang Handsome Intelligent Remanufacturing Technology Co.Ltd,jiaxing 314000,China [4]School of Materials Science and Engineering,Nanchang Hangkong University,Nanchang 330063,China

出　　处：《Acta Metallurgica Sinica(English Letters)》2021年第9期1234-1244,共11页金属学报（英文版）

基　　金：financially supported by the National Key Research and Development Program of China(No.2016YFB1100203)。

摘　　要：A ferrite–austenite 12CrNi2 alloy steel additively manufactured by laser melting deposition(LMD) was heat treated by direct quenching(DQ) and tempering inter-critical quenching(TIQ) at 800 ℃ for enhancing its strength–ductility balance. Both heat-treated alloy steels have the martensite–ferrite dual-phase(DP) microstructures. The volume fractions of martensite in the two treated alloy steels are nearly similar(~ 85 vol%), while the sizes of the prior austenitic grain for martensite are different. The martensite-dominated DP microstructure resulted in an obvious improvement in strength–ductility balance of the alloy steel. Compared with the DQ treatment, the multi-step TIQ treatment caused the strength–ductility balance of the alloy steel to be enhanced due to its higher total elongation. The better ductility of the TIQ-treated alloy steel can be attributed to the optimization of the microstructure. The preferred orientation of ferritic grain in the as-deposited alloy steel which was adverse to plastic deformation through dislocation slip was eliminated via the multi-step TIQ treatment. Moreover, the TIQ treatment promoted the formation of finer-grained martensite with larger areas of grain boundaries and twinning boundaries which resulted in the enhancement of the coordinated deformability of the martensite with the ferrite.

关 键 词：Laser melting deposition Alloy steel Dual-phase microstructure Mechanical property Work-hardening rate 

分 类 号：TG142.33[一般工业技术—材料科学与工程] TG156.3[金属学及工艺—金属材料]