TY - JOUR

T1 - Role of effective strain on the deformability of brittle Hf-based bulk metallic glass

AU - Kim, Song Yi

AU - Park, Eun Soo

AU - Eckert, Jürgen

AU - Lee, Min Ha

N1 - Publisher Copyright: © 2021 The Author(s)

PY - 2021/11/20

Y1 - 2021/11/20

N2 - Numerical finite element method (FEM) calculation results reveal that the effective strain differs between the ductile Zr-based bulk metallic glass and brittle Hf-based bulk metallic glass (BMG) during rolling at room temperature. The current results demonstrated that the deformation mechanism of ductile Zr-based bulk metallic glass can be explained by perceptibility of multiple shear bands formation, however, the deformation mechanism of brittle Hf-based bulk metallic glass is represented by uniformly distribution of effective strain through overall specimen rather than localized into shear band. The variation of stress and the distribution of effective strain change significantly near the surface region of a Hf-based bulk metallic glass plate with increasing number of rolling passes. Under elasto-plastic deformation by cold rolling, the brittle Hf-based BMG has a thickness strain (εt) of −0.012, and the neutral effective strain (εeff) is 0.011 at the thickness direction, respectively. We present experimental confirmation that when the applied effective strain can be adjusted to below 1.1% during elasto-plastic deformation then even the brittle as-cast Hf-based BMG can be deformed up to 44% thickness reduction and 23% width expansion after multi-pass cold rolling without fracture by localization of shear stress.

AB - Numerical finite element method (FEM) calculation results reveal that the effective strain differs between the ductile Zr-based bulk metallic glass and brittle Hf-based bulk metallic glass (BMG) during rolling at room temperature. The current results demonstrated that the deformation mechanism of ductile Zr-based bulk metallic glass can be explained by perceptibility of multiple shear bands formation, however, the deformation mechanism of brittle Hf-based bulk metallic glass is represented by uniformly distribution of effective strain through overall specimen rather than localized into shear band. The variation of stress and the distribution of effective strain change significantly near the surface region of a Hf-based bulk metallic glass plate with increasing number of rolling passes. Under elasto-plastic deformation by cold rolling, the brittle Hf-based BMG has a thickness strain (εt) of −0.012, and the neutral effective strain (εeff) is 0.011 at the thickness direction, respectively. We present experimental confirmation that when the applied effective strain can be adjusted to below 1.1% during elasto-plastic deformation then even the brittle as-cast Hf-based BMG can be deformed up to 44% thickness reduction and 23% width expansion after multi-pass cold rolling without fracture by localization of shear stress.

KW - Amorphous alloys

KW - Bulk metallic glass

KW - Cold rolling

KW - Effective strain

KW - Mechanical property

UR - http://www.scopus.com/inward/record.url?scp=85120650395&partnerID=8YFLogxK

U2 - 10.1016/j.jmrt.2021.11.072

DO - 10.1016/j.jmrt.2021.11.072

M3 - Article

AN - SCOPUS:85120650395

VL - 15.2021

SP - 6713

EP - 6720

JO - Journal of Materials Research and Technology

JF - Journal of Materials Research and Technology

SN - 2238-7854

IS - November-December

ER -