中文摘要：

为探索磁记忆信号在铁磁性材料裂纹扩展过程中的变化规律，以510L钢为研究对象，采集裂纹扩展过程不同区域的磁记忆信号，计算裂纹尖端的应力强度因子，分析疲劳断口形貌，探讨金属磁记忆方法对铁磁材料疲劳损伤与裂纹扩展检测的可行性，并建立裂纹尖端磁记忆信号梯度Kmax值和应力强度因子局之间的关系。结果表明：M（T）试样宏观切口处的磁记忆信号特征量比裂纹尖端应力集中处的磁记忆信号特征量明显；梯度墨。值和应力强度因子局在疲劳循环累积下均呈指数形式增加，从断裂力学角度说明Kmax反映疲劳累积损伤的可行性；磁记忆信号特征量△HP（y）及Kmax可以反映经过不同服役期的510L钢损伤情况，为再制造修复和加工提供依据。

英文摘要：

510L steel is chosen to study how magnetic memory signals change during ferromagnetic material＇s crack propagation process. To establish the relationship between the gradient Kmax of magnetic memory signals of the crack tip and its stress intensity factor K1, the magnetic memory signals in different regions on the test pieces are collected and analyzed, the stress intensity factors of crack tips are calculated, and the fatigue fracture surfaces are analyzed. The results show that the observed magnetic memory signal at the macro kerf of the test sample M（T） has larger amplitude than that at the zone of stress concentration of the crack tip. Both Kmax and K1 increase exponentially when the fatigue cyclic accumulates. It proves that Kmax can be used to quantify the cumulative fatigue damage from the viewpoint of fracture mechanics. The features of magnetic memory signal, AHp（y） and Kraal, can quantify the damages of 510L steel after different service periods, and provide solid references for the remanufacturing.