This disclosure relates to a grip design used in an in-situ deformation
stage and a galvannealed (GA) coated sample for conducting tensile test and
observing microstructural changes under scanning electron microscope (SEM).
Background
The formability of GA coating on steel is mostly governed by its
microstructure, the four Fe-Zn intermetallics that form during annealing. The
phases, having widely different crystallographic structure (ξ-monoclinic,
δ=hexagonal, =bcc and 1=fcc), are expected to possess diverse mechanical
properties. Hence the study of crack propagation through each of these phases
becomes necessary to understand the correlation of powdering and flaking with
different phase fractions which in turn depend upon the process parameters like
GA temperature, line speed and bath composition.
One of the ideal tests for this investigation is the in-situ deformation
study of the GA coated specimen under the in-situ deformation stage (shown in
FIG. 1) for SEM. This test is capable of developing data of the real time changes
in the GA microstructure under deformation, which in turn has the potential to
resolve many scientific curiosities. The conventional sample design for the in-situ
deformation studies in SEM is shown in FIG. 2.
The lateral view of the GA coating along with the steel sample during
deformation is very important so as to understand the behavior of both the steel
and GA coating together during tensile testing.
Because of the paucity of proper experimental technique, the lateral
assessment of deformation behavior of GA coating along with steel sample is not
possible.
Few developments have been done in this regard. US2011/0317157
discloses micro-scale testing stage used for testing micro-scale and nano-scale
sample e.g. metal, having micro-scale or nano-scale specimen with opposing
ends for inserting into pair of slots at free end of each beam. CN203405477
discloses an in-situ micro mechanical scanning electron microscope tester having
clamp body fixed with torsion shaft, where end of torsion shaft is connected with
spline shaft that is inserted in sleeve along axial direction. WO0163266 discloses
apparatus for imaging cross-section of work piece, including ion-projection

column to project image of aperture onto work piece to excavate portion of front
surface and expose cross-section which is imaged using particle beam column.
So far no such design is available for the in-situ deformation stage and
the sample in the public domain for lateral viewing of the GA coating along with
the steel sample during deformation.
Objects
In view of the foregoing limitations inherent in the prior-art, it is an object
of the disclosure is to develop a gripping arrangement and a sample design to
observe lateral deformation behavior of coating along with steel through in-situ
deformation stage in SEM.
SUMMARY OF THE DISCLOSURE
In one aspect, the disclosure provides a gripping arrangement for an in-situ
deformation stage. The gripping arrangement comprises a pair of grips, each
grips comprise a pair of extension in such a manner that the pair of extension
protrudes out from an edge of each grips. Each extensions comprises a grip hole,
the grip holes of respective pair of grips are coaxial to each other. A sample have
two ends, both ends comprises a sample hole, both the sample holes while the
sample is tested, is positioned between the grip holes in such a manner that
each sample holes is coaxial to the respective grip holes and a two separate pins
are inserted between the grip holes and the sample holes respectively.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
FIG. 1 shows an image of an in-situ deformation stage in accordance with an
embodiment of the disclosure.
FIG. 2 shows a conventional sample design to be mounted on the in-situ
deformation stage in accordance with an embodiment of the disclosure.
FIG. 3(a) shows an isometric view of a gripping arrangement to be mounted on
the in-situ deformation stage in accordance with an embodiment of the
disclosure.
FIG. 3(b) shows top view of the gripping arrangement to be mounted on the in-
situ deformation stage in accordance with an embodiment of the disclosure.

FIG. 4 shows a sample design to be mounted on the gripping arrangement of
the in-situ deformation stage in accordance with an embodiment of the
disclosure.
FIG. 5 shows the microstructure of the GA coating while it is being tested in the
in-situ deformation stage
Detailed Description
Various embodiments of the disclosure provide a gripping arrangement
for an in-situ deformation stage comprising, a pair of grips, each grips comprising
a pair of extension, the pair of extension protruding out from an edge of each
grips, each extensions comprising a grip hole, the grip holes of respective pair of
grips being coaxial to each other, a sample having two ends, each ends
comprising a sample hole, both the sample holes while the sample being tested,
is positioned between the grip holes in such a manner that each sample holes is
coaxial to respective and a two separate pins are inserted between the grip
holes, and the sample holes respectively.
Shown in FIG. 1 is an in-situ deformation stage (100). To the in-situ
deformation stage (100), a gripping arrangement (104) (shown in FIG. 3 (a)) is
configured. A cooling cylinder (108) is further configured to the in-situ
deformation stage (100) in order to cool the stage while sample is being pulled.
The in-situ deformation stage (100) along with the cooling cylinder (108)
is further configured to a scanning electron microscope (SEM) for observing the
tensile deformation of the sample.
Shown in FIG. 3(a) is an isometric view of the gripping arrangement
(104) comprising a pair of grips (112a, 112b). To fix the gripping arrangement
(104) over the in-situ deformation stage (100), holes (R1, R2, R3 and R4) on the
in-situ deformation stage (100) is provided as shown in FIG. 1. Subsequently
similar holes (r1, r2, r3, and r4) are also provided in the pair of grips (112a,
112b) respectively. Other means can also be used to fix the gripping
arrangement over the in-situ deformation stage.
Each grips (112a, 112b) comprises a pair of extensions (116a, 116b)
respectively. The pair of extensions (116a, 116b) protrudes out along an edge of
each grips (112a, 112b). The extensions can be made up of the same material as
that of the grip or can be of some other material suitable for the purpose.

Each pair of extensions (116a) comprises a grip holes (120a1, 120a2) and
similarly the pair of extensions (116b) comprises a grip holes (120b1, 120b2).
The extensions can be in the form of annular ring. The grip holes (120a1) and
(120a2) are coaxial to each other. Similarly, the grip holes (120b1) and (120b2)
are also coaxial to each other. Shown in FIG. 3(b) is the top view of the
gripping arrangement (104).
A sample (124) as shown in FIG. 4 has two ends, each ends comprises a
sample hole (124a, 124b). The shape of the sample (124) is such that one side
can be polished (hence flat) without much difficulty which is prerequisite to
observe any microstructure under scanning electron microscope. Therefore the
sample under scanning electron microscope is oriented in such a manner that the
electron beam faces the flat surface and curved surface is at the opposite end.
While performing tensile test over the sample (124), both the sample
holes (124a, 124b) are positioned between the grip holes (120a1, 120a2) and
(120b1, 120b2) respectively, in such a manner that each sample holes (124a,
124b) is coaxial to the respective grip holes (120a1, 120a2) and (120b1, 120b2).
Two separate pins (128a, 128b) are inserted between the grip holes and the
sample holes.
It should be appreciated that each pair of grips (112a, 112b) lie in the
same plane. Also axes of grip holes (120a1, 120a2) and (120b1, 120b2) are
parallel to each other.
It should also be appreciated that the pair of grips along with the pair of
extension and the two separate pins are part of the gripping arrangement (104).
Later on the pair of grips (112(a), 112(b)) is pulled apart, thereby pulling
the sample (124), so as to perform the tensile test.
The sample (124) is a GA coated steel having thickness in the range of
0.8 - 2 mm. The gripping arrangement could be extended to any kind of coated
samples.
In an embodiment, the pair of grips (112a, 112b) in the present
disclosure is made up of a hot rolled steel sheet.

Advantages:
Following are the advantages of the gripping arrangement of the
disclosure
1. Observation of the real time GA microstructural changes (along the
cross-section) due to deformation in SEM.
2. This design in principle can be used to study deformation and
fracture behaviors of any kinds of coating on sheets.
Example:
The shape of the GA coated steel sample to be observed in SEM under in-situ
deformation condition is shown in Fig. 4. It is hot mounted with conductive resin
and subsequently polished using 0.1 μm fine diamond paste. Afterwards, this
polished sample is fitted within the gripping arrangement (104) (Figs. 3 (a) and
(b)) and is mounted in the SEM chamber in in-situ deformation stage (100).
Subsequently the chamber is closed and the vacuum is on. After reaching the
requisite vacuum level, the deformation stage started pulling the sample and
now the microstructural changes that is occurring in the GA coating is depicted in
FIGS. 5 (a) & (b). Top layer 132a corresponds to coating layer i.e. GA layer and
a bottom layer 132b corresponds to steel layer. Thus the Fig. 5 is a real time
picture of the GA coating.

WE CLAIM
1. A gripping arrangement (104) for an in-situ deformation stage (100)
comprising:
a pair of grips (112a, 112b), each grips comprising a pair of extensions
(116a, 116b), the pair of extensions (116a, 116b) protruding out from an
edge of each grips, each extensions comprising a grip hole, thereby the
extensions (116a, 116b) having grip holes (120a1, 120a2) and (120b1,
120b2) respectively, the grip holes (120a1, 120a2) and (120b1, 120b2) of
respective pair of grips (112a, 112b) being coaxial to each other,
a sample (124) having two ends, each ends comprising a sample hole
(124a, 124b), both the sample holes (124a, 124b), while the sample
being tested, is positioned between the grip holes (120a1, 120a2) and
(120b1, 120b2) respectively in such a manner that each sample holes is
coaxial to respective grip holes and a two separate pins (128a, 128b) are
inserted between the grip holes (120a1, 120a2) and (120b1, 120b2), and
the sample holes (124a, 124b) respectively.
2. The gripping arrangement (104) for an in-situ deformation stage (100) as
claimed in claim 1, wherein each pair of grips lie in the same plane.
3. The gripping arrangement (104) for an in-situ deformation stage (100) as
claimed in claim 2, wherein axes of grip holes of respective pair of grips
are parallel to each other.
4. The gripping arrangement (104) for an in-situ deformation stage (100) as
claimed in claim 1, wherein the pair of grips is made up of hot rolled steel
sheet.
5. The gripping arrangement (104) for an in-situ deformation stage (100) as
claimed in claim 1, wherein the sample is coated.

6. The gripping arrangement (104) for an in-situ deformation stage (100) as
claimed in claim 5, wherein thickness of the sample including coating is in
the range 0.8 - 2 mm.