Fabrications and mechanical behaviors of amorphous fi bers?

Yi Jun?
(Laboratory for Microstructures,Institute of Materials,Shanghai University,Shanghai 200444,China)

Mechanical properties of micro-and nanoscale fi bers are superior to their bulk counterparts,and their mechanical behaviors are di ff erent froMeach other.Homogeneous amorphous fi bers with smooth surfaces and controllable sizes can be continuously drawn froMsupercooled liquid.Compared with the preparing of crystalline fi bers,the manufacturing of amorphous fi bers saves much energy and time.Furthermore,amorphous materials have excellent mechanical properties due to their short-ranged ordered and long-ranged disordered structures.Therefore,amorphous fi bers have wide engineering applications and research interest.In this paper we review the fabrication and mechanical behaviors of amorphous fi bers with excellent mechanical properties including oxide glass fi bers and amorphous alloy fi bers.

There are continuous and discontinuous oxide glass micro- fi bers.Discontinuous oxide glass micro- fi bers can be fabricated by techniques in which a thin thread of melt fl owing froMthe bottoMof a container is broken into segments.Continuous oxide micro- fi bers can be fabricated by techniques in which a fi lament of supercooled liquid is drawn froMmelt.However,oxide glass nano- fi bers can be fabricated by chemical vapor deposition,laser ablation,sol-gel,and thermal evaporation methods.Fabrication techniques of amorphous alloy fi bers are very di ff erent froMthose of oxide glass fi bers.These techniques adopt in-rotating-water spinning method,melt-extraction method,Taylor method,nanomoulding method,fast drawing method,melt drawing method,and gas atomization method.

Microscale oxide glass fi ber has a facture strength as high as 6 GPa.The fracture strength of nanoscale oxide glass fi ber can reach 26 GPa which is close to the theoretical strength of 30 GPa.On the other hand,the plasticity of microscale amorphous alloy fi bers is mediated by shear banding.The shear band spacing decreases with reducing sample size in bending.However,there is no tensile plasticity in microscale amorphous alloy fi bers.When the sample size is smaller than the size of shear band core(500 nm),inhomogeneous plastic deformation transforms into homogeneous plastic deformation.The tensile plasticity of amorphous alloy is signi fi cantly improved.The homogeneous plastic deformation is mediated by catalyzed shear transformation.The catalyzed shear transformation may be the origin of hardening behaviors of nanoscale amorphous alloy fi bers.

Fianlly,we summary the unsolved problems in the fabrications and mechanical behaviors of amorphous fi bers,and discuss the prospect of amorphous fi bers.

amorphous fi ber,supercooled liquid region,melt drawing,mechanical properties

?Corresponding author.E-mail:jxy305@gmail.com

31 May 2017;revised manuscript

5 July 2017)

10.7498/aps.66.178102

*Project supported by the National Basic Research PrograMof Chian(Grant No.2016YFB0700203)and the National Natural Science Foundation of China(Grant No.51501106).