二次时效温度对2.1 GPa不锈钢组织及性能的影响  

Effect of secondary aging temperature on microstructure and properties of 2.1 GPa stainless steel

作　　者：田帅 刘振宝[1] 邱雨 梁剑雄[3] 赵文宇 王晓辉[1] 孙永庆[1] 王长军[1] TIAN Shuai;LIU Zhenbao;QIU Yu;LIANG Jianxiong;ZHAO Wenyu;WANG Xiaohui;SUN Yongqing;WANG Changjun(Research Institute of Special Steels,Central Iron and Steel Research Institute Co.,Ltd.,Beijing 100081,China;Faculty of Materials Science and Engineering,Kunming University of Science and Technology,Kunming 650000,Yunnan,China;Central Iron and Steel Research Institute Co.,Ltd.,Beijing 100081,China)

机构地区：[1]钢铁研究总院有限公司特殊钢研究院,北京100081 [2]昆明理工大学材料科学与工程学院,云南昆明650000 [3]钢铁研究总院有限公司,北京100081

出　　处：《钢铁》2025年第2期110-118,共9页Iron and Steel

基　　金：超高强度不锈钢研制项目资助(冶23T60680B)。

摘　　要：超高强度不锈钢是1种具有超高强度以及良好耐蚀性的钢种,常常作为承力结构部件应用于航空、航天、海洋等领域。单纯提高超高强度不锈钢的强度不具有实际应用价值,未来超高强度不锈钢的发展除了要求超高强度外,应兼顾钢的塑性、韧性和良好腐蚀性能。为了突破2.1 GPa超高强度不锈钢强韧性匹配极限,利用SEM、XRD、TEM等表征手段,结合力学性能测试的方式,研究了二次时效温度对2.1 GPa不锈钢显微组织及力学性能的影响。结果表明,经过不同二次时效温度处理后,不锈钢在高位错密度的马氏体基体上弥散分布着大量纳米级第二相,这些第二相主要以M_(2)C和Laves相为主,同时,在马氏体板条界发现薄膜状奥氏体的存在。时效过程中伴随着M_(2)C和Laves相的析出、长大、粗化及奥氏体含量的升高,使得钢的强度和韧性均呈现出先升高后降低的趋势。时效温度为520℃时,钢的强韧性匹配达到最佳,相比于目前国外强度级别最高的超高强度不锈钢(Ferrium S53钢),2.1 GPa不锈钢的抗拉强度和屈服强度均提高了约200 MPa,伸长率、断面收缩率和冲击功与之相当。Ultra-high strength stainless steels often used as load-bearing structural component in aviation,aerospace,marine and other fields,due to its ultra-high strength and good corrosion resistance.For the ultra-high strength stainless steel,simply improving its strength is not enough for the practical application.The future development of ultra-high strength stainless steel should take the plastic,toughness and good corrosion properties of steel into account.In order to achieve the optimal combination of strength and toughness in 2.1 GPa stainless steel,the effects of secondary aging temperature on the microstructure and mechanical properties of 2.1 GPa stainless steel were studied by means of SEM,XRD,TEM and mechanical properties testing.The results show that a large number of nanoscale second phases are dispersed on martensitic matrix with high density dislocation after the steel is treated at different secondary aging temperatures.These second phases are mainly composed of Laves phase and M_(2)C phase.At the same time,thin film austenite is found in the boundary of martensitic lath.During the aging process,the precipitation,growth,coarsening of M_(2)C and Laves phases,as well as the increase in austenite content,result in an initial increase followed by a decrease in the strength and toughness of the steel.At 520℃aging,the strength and toughness of steel reach the best match.Compared with the current foreign strength level of the highest ultra-high strength stainless steel(Ferrium S53),the tensile strength and yield strength of 2.1 GPa stainless steel have increased by about 200 MPa,while the elongation,section shrinkage,and impact energy are comparable.

关 键 词：2.1 GPa不锈钢 M_(2)C相 LAVES相 时效温度 奥氏体 强韧性 力学性能 马氏体 

分 类 号：TG142.71[一般工业技术—材料科学与工程] TG156.92[金属学及工艺—金属材料]