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研究了超高强度板条马氏体钢的平面应变断裂韧性与缺口韧性、拉伸塑性之间的关系。实验结果表明，断裂韧性受控于裂尖前沿很小范围内（1—2倍临界裂纹张开位移c）显微组织的微观塑性，钝缺口韧性、拉伸塑性则受控于奥氏体晶粒尺寸或板条束直径。特征距离与裂纹尖端钝化所产生的有效变形区尺寸（2c）相对应。并提出断裂韧性与缺口韧性、拉伸塑性的关系取决于尖裂纹前沿有效变形区尺寸（2c）与原奥氏体晶粒尺寸（dγ）的相对大小。当2c＞（1－2dγ）时，两者的变化一致
The relationship between plane strain fracture toughness and notch toughness and tensile ductility of ultra-high strength martensitic steel was studied. The experimental results show that the fracture toughness is controlled by the microscopic plasticity of the microstructure, the ductile fracture toughness and the tensile ductility are controlled by the austenite crystal within a small range (1-2 times the critical crack opening displacement c) Grain size or slab beam diameter. The characteristic distance corresponds to the effective deformation zone size (2c) produced by the crack tip deactivation. The relationship between fracture toughness and notch toughness and tensile plasticity is determined by the relative size of the effective deformation zone (2c) at the front of the sharp crack and the original austenite grain size (dγ). When 2c> (1-2dγ), the two changes are consistent