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Preparation and Properties of New Fe-based Soft-magnetic Bulk Amorphous Alloys

Author: ZhangZhiChun
Tutor: LongZhiLin
School: Xiangtan University
Course: Materials Physics and Chemistry
Keywords: Iron-based bulk amorphous alloys Copper mold casting method Mechanical behavior Soft magnetic properties Corrosion
CLC: TG139.8
Type: Master's thesis
Year: 2008
Downloads: 56
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Abstract


The iron-based soft magnetic bulk amorphous alloys with low-cost, good soft magnetic characteristics and high strength, is a great application potential structural and functional materials. In this paper, micro-alloying technology, Fe-Co-B-Si-Nb-Cr and Fe-M-Hf-BY bulk amorphous alloys prepared by copper mold casting; help of the XRD, TEM, DSC and DTA and VSM Characterization of glass-forming ability and soft magnetic properties of two glass alloy systems; aid of dynamic potential polarization and nano-indentation technique to test the corrosion and mechanical properties of Fe-Co-B-Si-Nb-Cr glass alloy systems. Combined with the experimental data, a preliminary discussion of micro-alloyed alloy glass-forming ability, magnetic properties, corrosion and mechanical properties. The main results and conclusions are as follows: (1) Cr elements added, although slightly lower glass forming ability of the alloy Fe-Co-B-Si-Nb, but significantly improve the soft magnetic properties, mechanical properties and corrosion. Copper mold casting method, Fe-Co-B-Si-Nb-Cr alloy can be obtained to the maximum diameter of the glass rod of 4mm. These bulk amorphous exhibits a high saturation magnetic induction intensity (0.81-1.04T), the low coercive force (0.6-1.6A / m), the low Young's modulus (200-215GPa), about 2% of the elastic strain and plastic strain of 0.7%, also has high fracture strength (3840-4043MPa). Studied using depth-sensitive nano-indentation technique {[(Fe 0.6 Co 0.4 ) 0.75 B 0.2 Si < sub> 0.05 ] 0.96 Nb 0.04 } 96 Cr 4 bulk amorphous alloys at room temperature plastically deformed. Nanoindentation deformation behavior of the alloy loading rate: 0.75mN / s to 3mN / s loading rate found serrated flow; When increases to 6mN / s, the the serrated flow gradually disappeared. Further, when the Cr content is from 0-4 at.%, Fe-Co-B-Si-Nb-Cr bulk amorphous alloys in a 0.5 M NaCl solution, the corrosion rate and the corrosion current density of from 7.0 × 10 -1 mm / year reduced to 1.6 × 10 -3 mm / year, from of 3.9 × -6 A / the cm 2 is reduced to 8.7 × 10 -7 A / cm 2 . (2) a single roll method and copper mold casting prepared a the Fe 75-x the M x the Hf 3 the Y- 2 the of B of 20 (M = Co, Nb; x = 0,4 at.%) alloy system amorphous ribbon and amorphous rod samples and to test the difference between the amorphous alloy systems shown scanning calorimetry curve, X-ray diffraction patterns and soft magnetic properties. The results showed that a small amount of Nb or Co substitution Fe 75 Hf 3 Y 2 B 20 Fe element, The thermal stability and the glass-forming ability of the alloy significantly improved can be obtained. Which Fe 71 Nb 4 Hf 3 Y 2 B 20 supercooled liquid phase District the the width △ T x up to 75K, reduced glass transition temperature T rg 0.58, the critical diameter up to 4mm 0.97-1.08T, the saturation magnetic flux density of the amorphous The alloy also has a greater thermal stability, strong glass-forming ability, and good soft magnetic properties.

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CLC: > Industrial Technology > Metallurgy and Metal Craft > Metallurgy and Heat Treatment > The alloy learn with a variety of properties of alloys > Other special nature of the alloy > Amorphous alloy
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