Study On The Correlation Between The Heat Treatment Process Of FINEMET Alloy Melt And The Properties Of Ribbons

FINEMET alloy have attracted great interest due to their excellent soft magnetic properties.The paper focus on the relationship between the alloy melt heat treatment of alloy melt and the properties of amorphous ribbons.The main conclusion are as follows:The influence of temperature,heat retaining time and the process of heat treatment on the viscosity of Fe73.5Si13.5B9Nb3Cu1 alloys was systematically studied using a torsional oscillation viscometer.It is found that the melt structure change with temperature and the Liquid-Liquid structure transition occurs in the heating process of 1350??1400?.The experimental result shows that the higher melt heat treatment and longer time preservation promote the stability of 1K107 alloy melts,making the atomic cluster smaller and the melt more uniform.In order to investigate the influence Liquid-Liquid phase transition on the properties of the ribbon.The amorphous ribbons were prepared below and above the temperature of liquid-liquid phase transition and the properties were characterizsed.The experimental result shows that overheating of the melt above the temperature of liquid-liquid phase transition will promote stability of the melt pool and reduces bubbles of the wheel side surface and roughness of the air side,which in turn promotes the consistency of material surface quality.It also reduce the coercivity of amorphous ribbons and promote the high thermal stability and widen the heat treament temperature range of the best soft magnetic property.The amorphous ribbon was annealed below and above the glass trasition temperature,then the mechanical properties of ribbons were tested.The results verify that annealing can result in the decrease of the free volume in the amorphous alloys.When the annealing temperature is below the glass trasition temperature,the hardness of the alloy increase with the increasing of the annealing time,which is because of reduction of the free volume and hinder of the nucleation and movement of the shear band.However,when the annealing temperature is above the glass trasition temperature,the hardness of the alloy increase incipiently with the increasing of annealing time,and then decrease after reaching the peak value.This trend stems from inhibition of the nanocrystal.Nevertheless when the nanocrystal size exceeds the certain value,the nanocrystals will promote the formation of crack source.The crack result in the decreas of hardness.