Magnetization and Giant Magnetoimpedance Effect of Co-Rich Microwires under Different Driven Currents

Co68.25Fe4.5Si12.25B15amorphous microwires with a diameter of 34 μm were prepared via the melt extraction method. The dependency of AC driving currentIacand frequency on giant magnetoimpedance (GMI) effect and magnetization were investigated using a 4294A impedance analyzer and the transverse Kerr effect. The GMI effect was analyzed whenIacchanged from 6 mA to 20 mA at a frequency ranging from 0.1 MHz to 15 MHz. The influence of AC current dependent on the frequency is correlated with the magnetization mechanism. The maximum transverse Kerr intensity (MTKI) decreased with the increase inIacunder direct magnetic field when the frequency was below megahertz. However, MTKI values were similar with the increase ofIacwhen it was over 2 MHz. Meanwhile, the GMI effect was optimized by selecting an adequate value of AC driving currentIp, at which the circular permeability was higher when the frequency was not over 2 MHz. Results showed that the influence ofIacon magnetoimpedance became weak with strong skin effect and slightly stronger GMI effect driven by a higherIacwhen the frequency was between 2 MHz and 15 MHz. The skin effect turned out to be the key factor to the GMI effect; thus, there were no obvious differences in magnetization and GMI effect with AC driving current changing when the frequency was as high as 15 MHz.

Preparation of Ti-Based and Zr-Based Bio-Metallic Wires by Arc-Melting Type Melt-Extraction Method

New Ti-based and Zr-based metallic wires for the future application as biomaterials were developed by arc-melting type melt-extraction method. Zr-based metallic glass wire, -Ti type Ti-Zr binary wire and -Ti type Ti-Nb-Ta-Zr (TNTZ) wire show high tensile strength and good vending ductility. Zr-based metallic glass wire shows extremely high tensile strength over 1GPa and large elastic strain limit reached approximately 2%. Ti-Zr binary alloy shows high wire-shape forming tendency during melt-extraction, and high Ti concentration Ti90Zr10 alloy wire was obtained. TNTZ wire shows superior bending ductility and full ductility is achieved.

Preparation of Zr-based Metallic Glass Wire for Biomedical Application

New Zr based metallic glass wires without bio-toxic elements of Ni, Al and Be were devel-oped for the further application as biomaterials by arc-melting type melt-extraction method. The continuous metallic glass wires with a good white luster and smooth surface were obtained in Zr-Ti-Al-Co, Zr-Al-Co-Cu, Zr-Al-Co and Zr-Ti-Co alloys. The Zr-based metallic glass wires show high tensile strength reaching 1000MPa. Furthermore, the wires exhibit good bending duc-tility and can be bent through 180 degrees without fracture. The Zr-based metallic glass wires achieve simultaneously high tensile strength, good bending ductility and high thermal stability.

Production of Zirconium-Based Glassy Alloy Wires by Melt Extraction Method and Their Mechanical Properties

Glassy Zr65Al10Ni10Cu15 wires were produced in the diameter range up to about 310 µm by a melt extraction method using a copper wheel in an argon atomospher The grass transition temperature (Tg) and crystallization temperature (Tx) are 652K and 757K, respectively, and the temperature interval of the supercooled liquid, ΔTx(=Tx-Tg) is 105K, in agreement with those for the corresponding melt-spun ribbon. The wires have a nearly real circular cross section and good mechanical properties.