This paper reports a new technique, namely the
incremental micro-hole-drilling method (IμHD) for mapping
in-plane residual or applied stresses incrementally
as a function of depth at the micron-scale laterally and
the sub-micron scale depth-wise. Analogous to its
macroscale counterpart, it is applicable either to crystalline
or amorphous materials, but at the sub-micron scale.
Our method involves micro-hole milling using the
focused ion beam (FIB) of a dual beam FEGSEM/FIB
microscope. The resulting surface displacements are
recorded by digital image correlation of SEM images
recorded during milling. The displacement fields
recorded around the hole are used to reconstruct the
stress profile as a function of depth. In this way residual
stresses have been characterized around a drilled hole of
1.8microns. diameter, enabling the profiling of the stress
variation at the sub-micron scale to a depth of 1.8 microns.
The new method is used to determine the near surface stresses
in a (peened) surface-severe-plastically-deformed (S2PD)
Zr50Cu40Al10 (in atomic percent, at.%) bulk metallic glass
bar. In plane principal stresses of -800 MPa ± 90 MPa and
?600 MPa ± 90 MPa were measured, the maximum
compressive stress being oriented 15° to the axis of the bar.