Effects of adding B element on amorphous forming ability,magnetic properties, and mechanical properties ofFePBCCu alloy br

Fe-based amorphous alloys are widely used in power electronics fields such as transformers and reactors dueto their low coercivity, high permeability and low loss. However, the relatively low saturation magnetization(Bs) limits their further applications. Generally speaking, the adjustable magnetic Fe content as an effectivestrategy can ameliorate the magnetic properties, and the higher the Fe content, the higher the obtained Bs is,but the decrease of the corresponding non-magnetic element content will result in the drop of the ability ofalloys to form amorphous phase, leading to the deterioration of the magnetic softness and bending ductility ofnanocrystalline alloys. To address this critical issue, in this work, based on the metal-metalloid hybridization,the FePBCCu amorphous ribbons, each with a thickness of similar to 25 mu m, are prepared by the single-roller meltspinning method via 7% (atomic percent) B substitution for P, and the effects of B element addition on theability to form amorphous phase, magnetic properties and mechanical properties of ribbons are investigated.Thermodynamic behavior shows that the addition of small quantities of B element can reduce the structuralheterogeneity of alloy and the crystallization driving force as well, thus effectively improving the thermalstability of the amorphous matrix. The melting and solidification curves show that the addition of B canpromote alloy to approach to the eutectic composition, and there is a large degree of undercooling. As a result,the critical thickness of ribbons increases from similar to 21 mu m for B-free alloy to similar to 30 mu m for B-added alloy due to themicro-alloying effect. The addition of B increases the effective magnetic moment of magnetic atoms in alloy,resulting in the increase of the saturation magnetization. Furthermore, the results of nanoindentation tests showthat the modulus value of the B-added alloy decreases greatlyr and fluctuates in a smaller range than that ofthe B-free alloy, which is closely associated with the structural uniformity of the alloy