TY - JOUR
T1 - Cause of hardening and softening in the bulk glassy alloy Zr50Cu40Al10 after high-pressure torsion
AU - Adachi, Nozomu
AU - Todaka, Yoshikazu
AU - Yokoyama, Yoshihiko
AU - Umemoto, Minoru
N1 - Funding Information:
This work was performed with assistance from the Inter-University Cooperative Research Program (Grant No. 14G0010 ) of the Cooperative Research and Development Center for Advanced Materials, Institute for Materials Research, Tohoku University . This work was also partially supported by a Grant-in-Aid for Scientific Research (KAKENHI) (Grant No. 26630363 ) from the Japan Society for the Promotion of Science (JSPS) . The authors would like to express their thanks to Prof. O. Haruyama of Tokyo University of Science for useful discussions and advice on density measurements.
Publisher Copyright:
© 2015 Elsevier B.V.
PY - 2015/3/1
Y1 - 2015/3/1
N2 - The bulk glassy alloy (BGA) Zr50Cu40Al10 was deformed using high-pressure torsion (HPT), which resulted in severe plastic deformation. The Vickers hardness of the BGA after the HPT process indicated that the BGA experienced both softening and hardening. With the aim of identifying mechanisms for improving the mechanical properties of BGAs, the cause of these HPT-induced phenomena was investigated, while focusing on the free volume (FV) and the macroscopic residual stress. Although the total fraction of the FV increased after the HPT process in proportion to the introduced shear strain, the effect of the FV on the hardness was negligibly small. To control the residual stress in HPT-processed disks, anvils with radial grooves were used during the HPT process. It was observed that a residual stress develops in BGAs owing to inhomogeneous plastic flow (i.e., deformation with a strain gradient) during plastic deformation and that this stress causes the significant extents of softening and hardening observed. In other words, the mechanical properties of BGAs can be improved by introducing a residual stress.
AB - The bulk glassy alloy (BGA) Zr50Cu40Al10 was deformed using high-pressure torsion (HPT), which resulted in severe plastic deformation. The Vickers hardness of the BGA after the HPT process indicated that the BGA experienced both softening and hardening. With the aim of identifying mechanisms for improving the mechanical properties of BGAs, the cause of these HPT-induced phenomena was investigated, while focusing on the free volume (FV) and the macroscopic residual stress. Although the total fraction of the FV increased after the HPT process in proportion to the introduced shear strain, the effect of the FV on the hardness was negligibly small. To control the residual stress in HPT-processed disks, anvils with radial grooves were used during the HPT process. It was observed that a residual stress develops in BGAs owing to inhomogeneous plastic flow (i.e., deformation with a strain gradient) during plastic deformation and that this stress causes the significant extents of softening and hardening observed. In other words, the mechanical properties of BGAs can be improved by introducing a residual stress.
KW - Bulk amorphous alloys
KW - Hardness
KW - Mechanical property
KW - Residual stresses
KW - Severe plastic deformation
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U2 - 10.1016/j.msea.2014.12.101
DO - 10.1016/j.msea.2014.12.101
M3 - Article
AN - SCOPUS:84921453359
VL - 627
SP - 171
EP - 181
JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
SN - 0921-5093
ER -