Magneto-plasticity occurs when a weak magnetic field alters material plasticity and offers a viable so-lution to enhance ductile-mode cutting of brittle materials.This study demonstrates the susceptibility of non-magnetic single-crystal calcium fluoride(CaF2)to the magneto-plastic effect.The influence of magneto-plasticity on CaF2 was confirmed in micro-deformation tests under a weak magnetic field of 20 mT.The surface pile-up effect was weakened by 10-15 nm along with an enlarged plastic zone and suppressed crack propagation under the influence of the magnetic field.Micro-cutting tests along differ-ent crystal orientations on the(111)plane of CaF2 revealed an increase in the ductile-brittle transition of the machined surface with the aid of magneto-plasticity where the largest increase in ductile-brittle transition occurred along the[112]orientation from 512 nm to a range of 664-806 nm.Meanwhile,the subsurface damage layer was concurrently thinner under magnetic influence.An anisotropic influence of the magnetic field relative to the single-crystal orientation and the cutting direction was also observed.An analytical model was derived to determine an orientation factor M that successfully describes the anisotropy while considering the single-crystal dislocation behaviour,material fracture toughness,and the orientation of the magnetic field.Previously suggested theoretical mechanism of magneto-plasticity via formation of non-singlet electronic states in defected configurations was confirmed with density func-tional theory calculations.The successful findings on the influence of a weak magnetic field on plasticity present an opportunity for the adoption of magnetic-assisted micro-cutting of non-magnetic materials.

Yunfa Guo;Yan Jin Lee;Yu Zhang;Anastassia Sorkina;Sergei Manzhos;Hao Wang

Department of Mechanical Engineering,National University of Singapore,9 Engineering Drive 1,Singapore 117575,Singapore;School of Materials and Chemical Technology,Tokyo Institute of Technology,Ookayama 2-12-1,Meguro-ku,Tokyo 152-8552,Japan

材料科学技术（英文版）

[1]Yunfa Guo;Yan Jin Lee;Yu Zhang;Anastassia Sorkina;Sergei Manzhos;Hao Wang-.Effect of a weak magnetic field on ductile-brittle transition in micro-cutting of single-crystal calcium fluoride)[J].材料科学技术（英文版）,2022(17):96-113

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