Pronounced enhancement of glass-forming ability of Fe-Si-B-P bulk metallic glass in oxygen atmosphere
- PDF / 409,155 Bytes
- 6 Pages / 584.957 x 782.986 pts Page_size
- 26 Downloads / 180 Views
hua Zhangb) College of Electrical and Power Engineering, Shanxi Key Laboratory of Coal Mining Equipment and Safety Control, Taiyuan University of Technology, Wanbolin District, Taiyuan, Shanxi 030024, China
Baolong Shen School of Materials Science and Engineering, Southeast University, Jiangning District, Nanjing 211189, China
Weihua Wang Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Akihisa Inoue Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Zhenhai District, Ningbo, Zhejiang 315201, China (Received 14 December 2013; accepted 17 April 2014)
It is widely accepted that oxygen will severely deteriorate the glass-forming ability (GFA) of an alloy. In this work, we report that the GFA of a Fe76Si9B10P5 glassy alloy can be significantly improved (the critical diameter for fully glass formation is increased from 1 to 3 mm) under oxygen casting atmosphere. Furthermore, the pressure of oxygen atmosphere gives an obvious enhancement in the critical diameter of Fe76Si9B10P5 glassy alloy. A dependence of GFA on casting atmosphere species (argon, nitrogen, air, and oxygen) is also observed for this glassy alloy, and its critical diameter is 1, 1.5, 2.5, and 3 mm, respectively. In addition, the Fe-based glassy alloy exhibits excellent soft magnetic properties regardless of the applied casting atmosphere. The mechanism for such an unusual oxygen effect on the GFA of Fe76Si9B10P5 glassy alloy is attributed to the reduced nucleation rate caused by the enhancement of surface tension of the alloy melt.
I. INTRODUCTION
Fe-based bulk metallic glasses (BMGs) possess considerably superior properties including high strength, good magnetic properties, abundant natural resources, low material cost, etc. Such unique properties enable them to be candidates for magnetic functional applications.1–3 However, the soft magnetic Fe-based MGs usually have poor glass-forming ability (GFA). To improve the GFA of Fe-based glassy alloys, great efforts have been devoted and many strategies have been used. These strategies can be divided into two categories: one is to scavenge heterogeneous nucleation sites out of the undercooled liquids of alloys and the other is through adjusting the compositions of alloys. There are some special strategies for scavenging the heterogeneous nucleation sites in Fe-based alloys, such as pure raw materials, flux melting, minor rare earth elements doping, and ultrahigh vacuum casting.4–14
Address all correspondence to these authors. a) e-mail: [email protected] b) e-mail: [email protected] DOI: 10.1557/jmr.2014.96 J. Mater. Res., Vol. 29, No. 10, May 28, 2014
http://journals.cambridge.org
Downloaded: 24 Feb 2015
However, these strategies may lead to increases in the unit cost and the cycle time for the production of BMGs, and limit their industrial applications. Especially, it is widely accepted that oxygen severely deteriorates the GFA of an alloy, and the metallic glasses have usually been prepared in high vacuum or argon atmosphere. For addi
Data Loading...
