The Influence of Internal Stress on the Nanocrystal Formation of Amorphous Fe73.8Si13B9.1Cu1Nb3.1 Microwires and Ribbons

Abstract

The early stages of nanocrystallization in amorphous Fe73.8Si13B9.1Cu1Nb3.1 ribbons and microwires were compared in terms of their internal stress effects. The microstructure was investigated by the X-ray diffraction method. Classical expressions of crystal nucleation and growth were modified for microwires while accounting for the internal stress distribution, in order to justify the XRD data. It was assumed that, due to the strong compressive stresses on the surface part and tensile stresses on the central part, crystallization on the surface part of the microwire proceeded faster than in the central part. The results revealed more rapid nanocrystallization in microwires compared to that in ribbons. During the initial period of annealing, the compressive surface stress of a microwire caused the formation of a predominantly crystallized surface layer. The results obtained open up new possibilities for varying the high-frequency properties of microwires and their application in modern sensorics.

Influence of the Geometrical Aspect Ratio on the Magneto-Structural Properties of Co2MnSi Microwires

“…This manufacturing process is particularly advantageous for alloys containing manganese, as it protects against oxidation by the surrounding glass layer due to the rapid solidification [29]. The origins of mechanical internal stresses in glass-coated ferromagnetic microwires are attributed to several factors, such as the difference in the thermal expansion coefficients of metallic alloys solidifying inside the glass coating, the quenching stresses related to the rapid quenching of the metallic alloy, and the drawing stresses [22,[26][27][28][29][30][31][32][33][34][35][36]. The internal stresses induced by the difference in the thermal expansion coefficients of the metallic alloy and the glass coating are the largest, being an order of magnitude higher than the other stresses [22,26,36,37].…”

Influence of a Protective Coating on the Crystallization of an Amorphous Fe78Si13B9 Alloy

“…Nanocrystalline materials formed on the basis of amorphous alloys attract great attention due to their unique physical properties [1][2][3][4][5]: strength (Al-based alloys [6]), magnetism (Fe-, Co-based [5,[7][8][9][10][11][12][13]), corrosion resistance [14][15][16], etc. The properties of amorphous alloys can be significantly improved through forming an amorphous nanocrystalline structure.…”

“…The formation of an amorphous nanocrystalline structure in the alloy of the Fe-Si-B system made it possible to significantly increase the saturation magnetization (by 40%) and surpass the level of saturation magnetization for Finemet-type alloys [28]. Amorphous Fe-Si-B alloys belong to one of the most widely studied groups of amorphous alloys [11,[28][29][30]. The processes of crystallization during conventional heating [25,28], rapid heating [31], high-pressure torsion deformation, multiple rolling methods [28,32], crystallization under widthwise/lengthwise press, and annealing [30] were studied for alloys of different chemical compositions.…”