Observation of lattice defects, deformation behavior in duplex alloys and evaluation of their lifetime using magnetic properties.

金属材料在疲劳变形过程中会产生大量的位错和面错。高密度晶格缺陷附近的应力集中引发微裂纹，最终发生断裂。为了理解变形机制和评估可靠性，观察位错等晶格缺陷是必要的。通常，使用电子显微镜进行晶格缺陷的观察。然而，由于位错附近的高残余应力，很难获得有关位错性质的准确信息。众所周知，磁性对铁磁材料中的晶格缺陷非常敏感。用磁性技术观察到了晶格缺陷。本工作制备了含小γ析出相的FeAl、Fe_3Al和Ni_3（Al，Ti）单晶体，用磁法研究了它们的形变行为和疲劳行为。形变对FeAl和Fe_3Al的高场磁化率和自发磁化强度都有影响。高场磁化率的各向异性决定了位错和平面断层的类型。FeAl的寿命可以通过监测自发磁化强度来估计，因为在疲劳过程中，在断裂之前，自发磁化强度迅速增加。

Numerous dislocations and planar faults in metallic materials are introduced during fatigue deformation. Stress concentration near high density of lattice defects initiates a microcrack and finally fracture occurs. To understand the deformation mechanism and evaluate the reliability observation of lattice defects such as dislocations is necessary.. In general, the observation of lattice defects is performed using electron microscope. However, it is very difficult to obtain exact information about nature of dislocations due to high residual stress near the dislocations. It is known that magnetic properties are very sensitive to lattice defects in ferromagnetic materials. The lattice defects have been observed by magnetic technique. In this work, deformation behavior of FeAl, Fe_3Al and Ni_3(Al,Ti) containing small γ precipitates single crystals were prepared and their fatigue behavior was examined by magnetic technique. High-field susceptibility and spontaneous magnetization in FeAl and Fe_3Al were influenced by deformation. Type of dislocation and planar faults were determined by anisotropy of high field susceptibility. Lifetime of FeAl can be estimated by monitoring spontaneous magnetization because the spontaneos magnetization rapidly increases just before fracture during fatigue.