Local crystallization investigation of amorphous alloys using a two-dimensional detector by X-ray diffraction method

Abstract

Amorphous alloys without a crystalline structure exhibit excellent soft magnetic properties but are difficult to machine due to their tough mechanical properties. The authors have proposed a new machining method that improves machinability by crystallizing only the local regions involved in machining, thereby reducing local strength and toughness. To realize this method, it is necessary to evaluate the crystallinity of the local area nondestructively, but it is difficult to detect a local area of crystals precipitated in amorphous materials by the conventional X-ray diffraction method (sin²ψ method). In this paper, we attempted to investigate the crystallinity of the local area using a two-dimensional X-ray diffraction method (2D method) with a two-dimensional detector. Fe-based amorphous alloys were locally crystallized using an ultrashort pulsed laser with a beam diameter of about 66 μm. Then, it was revealed that the 2D method can evaluate even a small area of crystallization within several tens of micrometers.