10Ni3MnCuAl钢动态断裂过程中二次裂纹扩展机制

Second Propagation Mechanism in Dynamic Fracture for Die Steel 10Ni3MnCuAl

研究了10Ni3MnCuAl模具钢动态断裂过程中二次裂纹扩展现象。结果表明，二次裂纹扩展与动态断裂裂纹由韧窝向准解理形态转变相一致。根据位错贫化带理论，裂纹尖端发射的位错将在沉淀析出的金属间化合物前塞积和缠结。由于位错的这一分布形态，导致了10Ni3MnCuAl钢在动态断裂中由韧窝向准解理的转变。同时，该钢沉淀析出大量弥散分布的金属间化合物Al3Ni，阻碍了裂尖发射的位错进一步运动，使之产生塞积和缠结，这是导致动态断裂二次裂纹扩展的重要原因。

Second propagation of dynamic fracture for the Die Steel 10Ni3MnCuAl has been inves tigated. The results have shown that the second propagation is coordinated with the transition from mi crovoids into cleavages in dynamic fracture. On the theory of dislocation free zone, crack tip emitted the dislocations , which piled up the tangled in ahead of the intermetallic compounds. Owing to action of the dislocations emitted, there was the transition from microvoids to cleavages in dynamic fracture of 10Ni3MnCuAl. It is also important that there were quantities of the fine intermetallic compounds which were precipitated from the matrix of martensite and this special structure resulted in second propagation in dynamic fracture