论文部分内容阅读
本文试图通过断口宏观和微观分析,联系65Nb钢冲击、扭转、压缩、弯曲、断裂韧性等性能的对应关系,探讨65Nb钢的断裂机制。试验结果表明65Nb钢经淬火回火后的微观断口是准解理型,且具有某些不同于结构钢的特点。发现同类型准解理断裂撕裂棱的形状、尺寸、分布的差异标志着材料强韧性的差别。准解理断裂机制最本质的是微裂纹连结前基体的微区塑性变形能力。不同应力状态导致不同的断裂机制。
In this paper, we attempt to discuss the fracture mechanism of 65Nb steel through the macroscopic and microscopic analysis of the fracture and the relationship between the impact, torsion, compression, bending and fracture toughness of 65Nb steel. The experimental results show that the micro-fracture of the 65Nb steel after quenching and tempering is a quasi-cleavage type and has some characteristics that are different from the structural steel. It is found that the difference of shape, size and distribution of the same type of quasi-cleavage fracture tearing edge indicates the difference of material toughness. The most essential feature of the quasi-cleavage fracture mechanism is the micro-zone plastic deformation capacity of the matrix before the micro-crack connection. Different stress states lead to different fracture mechanisms.