几种合金钢断裂机理与宏观断裂方向的研究

通过研究几种合金钢在常规破坏试验和复合型断裂试验过程中的断裂现象,分析不同应力状态下的断裂试验结果,发现随应力三维度由大到小变化,材料的断裂形式依次为组织断裂、孔洞正断、孔洞剪断、塑性剪断及焊合。且发生孔洞剪断时,危险点位于应力场中应力三维度取极大值处;发生塑性剪断时,危险点位于应力场中等效应力取极大值处,断裂方向均为危险点处最大剪应力作用面方向。

Research on Several Facture Mechanism and Macro-Fracture Direction in Several Types of Alloy Steels

By investigating the fracture phenomena of several types of alloy steels in the process of conventional destructive test and mixed fracture test,several macroscopic fracture forms under different stress triaxiality are analyzed.It is found that with the variation in stress triaxiality from the big to the small,the fracture mechanism of materials is in the sequence of cleavage,traction fracture,shear fracture with cavity,plastic shear fracture and seam,and also that when the shear fracture with cavity takes place,the fracture dangerous point is in the position where the stress triaxiality maximum value is taken in the stress field,and when the plastic shear fracture occurs,the fracture dangerous point is in the position where the equivalent stress maximum value is taken in the stress field.Accordingly,the fracture direction is in the direction of the dangerous points where the maximum shear stress action face.