Supplementary Information 13
To study the effect of temperature on the compressi
on yield strength,
σ
y
, we performed
uniaxial compression test at different temperatures
using a Cu
60
Zr
40
metallic glass sample
of the dimensions of 10x5x20 nm
3
(in the
x
,
y
and
z
directions, respectively) with PBCs
in all dimensions resembling the bulk state of the
material. The typical engineering stress)
strain curves are presented in Fig. S1(a) for the t
emperature range of 50 K (~ 0.06 T
g
) to
480 K (~ 0.6 T
g
). Fig 1(a) clearly shows that the peak stress (
i.e.
the yield strength,
σ
y
) of
the MG sample reduces by increasing the temperature
. It is understood that
2)4
the
mechanical failure of bulk metallic glasses at tem
peratures lower than the glass transition
temperature (T
g
) arises from the result of localized shearing indu
ced by the applied
stress.
3
Indeed, the applied stress biases the local energy
landscape by making some
relatively unstable atomic clusters undergo shearin
g to form shear transformation zones
(STZs),
2
which in turn leads to initiation and propagation
of shear bands (SBs) along the
principle shear direction. In the formation of STZs
, the applied stress and temperature
collaborate, that is, increasing the temperature fa
cilitates the formation of STZs at lower
applied stresses.
2, 5
Consequently, increasing the temperature reduces t
he mechanical
strength of the glass. Fig. 2(b) shows the variatio
n of yield strength against temperature
obtained from our simulations (the scattered dots),
as well as the linear approximation
(dashed)line) employed in the discussion of our exp
erimental results. It can be seen that
in the temperature range of our experiments (130 K
to 300 K), the MD results confirm
the linear dependence (slope ~ 3x10
)3
) of the compressive yield strength on the
temperature.
Fig. S1|
(a)
Engineering stress)strain curves for the Cu
60
Zr
40
metallic glass under
uniaxial compression test at different temperatures
from 50 K to 480 K.
(b)
Variation of
yield strength, σ
y
, with temperature at the temperature range of our
experiments (130 K)
300 K) obtained from molecular dynamics (scattered
dots) and the suggested linear
approximation to explain the experimental results (
dashed)line).