Dr. Guangping Zheng
The Hong Kong Polytechnic University, China
Title: Boundary Engineering in Improving Mechanical Strength and Ductility of Metallic Nano-glasses
Abstract:
The newly developed metallic glasses (MGs) termed as nano-glasses
(NGs) consist of glassy nanoparticles or nano-grains connected by glass-glass
interfaces (GGIs) or boundaries. They are believed to be effective in enhancing
the plasticity of MGs which might have a relatively low yield strength ADDIN
NE.Ref.{D29D9BD3-E063-40AA-829E-8465DFCBF1E9}. The plastic deformation
of NGs is attributed to the interaction between shear bands and the glass-glass
interfaces or boundaries. The boundaries with high concentration of free
volumes could act as nucleation sites for numerous shear transformation zones,
giving rise to homogenous deformation in NGs. However, the intrinsic high concentration
of free volumes in the glass-glass boundaries leads to the lack of a good
combination of high mechanical strength and ductility of NGs. In this work, the
influences of GGIs on mechanical properties of (Fe, Co)-based metallic
nano-glasses as prepared by pulse electrodeposition are investigated. Computer
simulation methods are developed to explore the improvement on mechanical
strength and ductility of NGs through boundary engineering. The experimental
and simulation results reveal that the mechanical properties of NGs could depend
on the structural and composition inhomogeneities across GGIs. It is found that
the issues of trade-off between mechanical strength and ductility in NGs could
be resolved through boundary or GGI engineering. (* This work is supported by the Green Tech Funds #
GTF202020103 from EPD of HKSAR, China)
Biography:
Dr. Guangping Zheng is currently an Associate Professor in Department of
Mechanical Engineering at the Hong Kong Polytechnic University. His research areas
are computational materials science, nanomechanics, mechanical properties and
deformation mechanisms of bulk metallic glasses, metallic nano-glasses and
high-entropy alloys. He has published more than 240 papers in refereed journals.