增材制造高强钢中的马氏体组织与马氏体相变  

Martensite microstructure and martensitic transformation of additive manufacturing high-strength steel

作　　者：汤隽劼 喻异双 胡斌[1] 熊智慧 刘仕龙 金学军[1,2] TANG Junjie;YU Yishuang;HU Bin;XIONG Zhihui;LIU Shilong;JIN Xuejun(School of Material Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;School of Biomedical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]上海交通大学材料科学与工程学院,上海200240 [2]上海交通大学生物医学工程学院,上海200240

出　　处：《钢铁》2024年第6期83-93,154,共12页Iron and Steel

基　　金：国家自然科学基金青年基金资助项目(52101045);中国博士后科学基金面上资助项目(2023M732192)。

摘　　要：马氏体组织因其与多种强化机制兼容,是高强钢追求极致强塑匹配的理想组织。传统马氏体组织以板条或针状结构为主,而对于采用金属增材制造技术加工的高强钢而言,极快的冷却速率、循环热输入和扫描式的加工模式决定了其组织的非平衡性,高能热输入引入的胞结构、元素偏聚、位错塞积及原奥氏体母相组织均区别于传统高强钢。这些与传统减材加工的区别给增材制造高强钢的性能调控和组织强韧化带来了全新挑战,常规后处理工艺与增材高强钢适配性差,亟需依据增材高强钢的微观组织和马氏体相变特点设计更合适的强韧化组织和后处理路线。简析了金属增材制造技术的发展脉络及当前面临的强塑性、强韧性制约瓶颈,归纳了增材制造高强钢中多层级马氏体组织与板条等传统马氏体组织相比所具有的多组元、亚稳态、多尺度特点,以金属增材加工涉及的两个相变过程(凝固和马氏体相变)切入,从高冷速、循环热输入的工艺特点和化学成分梯度、位错分布、母相组织等微观特征阐释这些组织和性能差异性的成因,归纳了成分、热处理、组织设计等对增材高强钢进行改性和强韧化的可行方法,最后总结了当前增材制造高强钢中的马氏体组织研究进展与热点方向,为日后增材制造马氏体高强钢的发展与推广提供借鉴及指导。Martensite microstructure,which is compatible to multiple strengthening mechanisms,is the ideal matrix for high-strength steel seeking ultimate strength and ductility.Traditional martensite is of lath or lenticular shape,but as for additive manufacturing(AM)high-strength steel,its ultra-high cooling rate,cyclic heat input and scanning mode makes the microstructure highly non-equilibrated.The massive energy input leads to cellular structure,alloying elements segregation,dislocation piling-up and prior austenite distinct from conventional high-strength steel.Such differences from traditional subtractive processing bring new challenges to performance control and microstructure design of AM high-strength steel.Conventional post-processing methods fit poorly with AM high-strength steel,and there is an urgent need for more appropriate microstructure and processing deign based on microstructural characteristics of AM steel.A brief analysis concerning current development of metal AM techniques and trade-off between strength and ductility were made,along with a summary on the multiphase,metastable,and multiscale characteristics of martensite structure in AM high-strength steel compared to traditional martensite laths.Starting from the two transformation stages involved in metal additive processing(i.e.solidification and martensite transformation),the differences from the processing characteristics like high cooling rate and cyclic energy input were explained,as well as microstructure characteristics such as composition gradient and dislocation distribution.Additionally,plausible methods for microstructural design and modification of AM high-strength steel including chemical processing and optimization were concluded,and current research progress and heated directions in AM high-strength steel were inducted,which may provide guidance for the promotion of AM martensitic high-strength steel in a foreseeable future.

关 键 词：金属增材制造 先进高强钢 马氏体相变 微观组织设计 力学性能调控 

分 类 号：TG142.2[一般工业技术—材料科学与工程]