Effect of short-time low-temperature austenitizing on microstructure and mechanical properties of DT300 ultra-high strength steel fabricated by laser powder bed fusion

作     者：Chen-yang Jiang Xiao-qiang Li Jin-tao Wang Hao Luo Sheng-qing Gao Sheng-guan Qu Chao Yang Chen-yang Jiang;Xiao-qiang Li;Jin-tao Wang;Hao Luo;Sheng-qing Gao;Sheng-guan Qu;Chao Yang

作者机构：National Engineering Research Centre of Near-Net-Shape Forming for Metallic MaterialsSouth China University of TechnologyGuangzhou 510640GuangdongChina Institute of New MaterialsGuangdong Academy of ScienceGuangzhou 510650GuangdongChina 

出 版 物：《Journal of Iron and Steel Research(International)》 (钢铁研究学报（英文版）)

年 卷 期：2024年第31卷第7期

页      面：1763-1777页

核心收录：

学科分类：0806[工学-冶金工程] 08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：funded by the Science and Technology Project of Guangdong Province (2020B090923001) Guangdong Basic and Applied Basic Research Foundation (2023A1515010384) The Fundamental Research Funds for the Central Universities (2023ZYGXZR005) 

主　　题：DT300 ultra-high strength steel Laser powder bed fusion-Short-time low-temperature austenitizing Microstructure Mechanical property 

摘      要：To address the inhomogeneous microstructure and improve the mechanical properties of DT300 ultra-high strength steel specimens fabricated by laser powder bed fusion,different post-heat treatment schedules are *** the increase in austenitizing temperature and time,the migration rate of austenite grain boundaries continuously increases with the dissolution of nano-carbides,and the formation of nano-oxides and twin martensite is also inhibited *** rapid growth in the size of prior austenite grains and martensite laths,as well as the decrease in the content of nano-oxides and twin martensite,led to a rapid decrease in the strength(yield strength and ultimate tensile strength)from HT2 to HTF *** HT1 specimens(austenitizing at 830℃for 30 min,then oil quenching and tempering at 300℃for 120 min and finally air cooling)display excellent mechanical properties of yield strength of 1572 MPa,ultimate tensile strength of 1847 MPa,elongation of 9.84%,and fracture toughness of 106 MPa m^(1/2),which are counterparts to those of conventional DT300 steel forgings after heat treatment.