探索强韧化机理,创新超高强度高韧性不锈钢

Strengthen-toughening mechanisms and development of new type ultra-high strength stainless steel

评述了超高强度钢和高强度不锈钢的基本理论、成分设计、超纯净熔炼和工程应用技术发展状况、在航空、航天及其他高科技领域中的应用和重要地位、发展目标、强韧化机理和成分探索研究现状及存在问题。借助透射电子显微镜高分辨和电子选区衍射等方法,揭示了超细马氏体板条、超细共格沉淀强化相Laves相、M2C及逆转变奥氏体等强 韧化机理。用VIM+VAR双真空超纯洁熔炼、超均匀加工及控制相变热处理等技术,获得2种低碳超高强度高韧性不锈钢,其力学性能分别达到抗拉强度1915MPa和1862MPa,断裂韧度119MPa·m1/2和120MPa·m1/2。

The fundamental theory, future object, studying status and topics of ultra-high strength steel and high strength stainless steel were reviewed. The new strengthen-toughening mechanisms, such as ultrafine martensitic laths, ultrafine strengthening phases M_2C carbide and Laves phase precipitated coherence with martensitic matix and reverse transformed austenite distributed over the effective grain boundaries were discovered with electronic microscopy. By means of VIM+VAR double vacuum melting technology secured super pure materials and by the super homogenization hotwork and controlling martensitic transformation heat treatment techniques, the new types of low carbon ultra-high strength steel in combination with high toughness were obtained. The tensile strengths reach 1 915 MPa and 1 862 MPa and the fracture toughnesses reach 119 MPa and 120 MPa·m^(1/2) respectively.