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arXiv 1902.03579cond-mat.mtrl-sci
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低周疲劳断裂转变特征

Features of low-to-high cycle fatigue fracture transition

Leonid Kremnev, Vyacheslav Matyunin, Artem Marchenkov, Larisa Vinogradova

摘要:

实验证实,如果钢的循环应力降低到小于拉伸屈服应力值,即在高周疲劳的情况下,断裂机制从位错转变为空位。这一结论是基于液体置换法测得的钢密度在超过拉伸屈服应力值的循环载荷作用下,无论是初始状态还是断裂后,均小于钢的密度。在后一种情况下,钢的硬度增加,而在小于其拉伸屈服应力值的循环应力下断裂的钢的硬度没有变化。这意味着,在这种情况下,金属断裂没有应变硬化,即经历脆性断裂发展的空位机制,而不是位错机制。结果,这种钢获得了类似于其暴露于辐射后出现的结构和性能,即脆性和脆性。所获得的结果使我们能够解释在Wöhler疲劳失效图中水平截面的存在

英文摘要:

It was experimentally confirmed that if steel cyclic stress reduces to less than tensile yield stress values, i.e. in case of high-cycle fatigue, the mechanism of fracture changes from dislocation to vacancy one. This conclusion was based on the fact that steel density determined by the method of liquid displacement is less than that of steel in both initial condition and after fracture under the cyclic loads exceeding tensile yield stress values. In the latter case steel hardness increases, whereas the steels fractured under the cyclic stresses less than their tensile yield stress values show no change in hardness. It means that in such a case metal fractures without strain hardening, i.e. undergoes brittle fracturing developing by vacancy mechanism rather than by dislocation one. As a result such steel obtains the structure and properties similar to those appearing after its exposure to radiation, i.e. friability and brittleness. The results obtained allow us to explain the presence of a horizontal section in the Wöhler fatigue failure diagram

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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