[CR4102] Tribology Assignment-118CR0129 Tribological study of a ternary carbide namely Ti3SiC2, a thermodynamically stable laminates, exhibits both Metallic and Ceramic features. Here we discussed about the properties, structure, R-curve, fretting and tribological behavior of Ti3SiC2 by taking references from various frontline researchers.

1. TRIBOLOGICAL STUDY OF TI3SIC2
N A M E - B I S W A J I T K A L O
R O L L N O - 1 1 8 C R 0 1 2 9
C O U R S E : [ C R 4 1 0 2 ] T R I B O L O G Y O F M A T E R I A L S
C O U R S E M E N T O R : P R O F . D E B A S I S H S A R K A R
D E P A R T M E N T O F C E R A M I C E N G I N E E R I N G ,
N A T I O N A L I N S T I T U T E O F T E C H N O L O G Y , R O U R K E L A

2. INTRODUCTION
 It’s documented that a serious limitation of ceramics for
various applications is the brittleness or poor fracture
toughness.
 This has motivated researches to develop toughened
ceramics either by composite/laminate approach or by
engineering the composition/microstructure of ceramic
monoliths.
 Recently, the research on ternary carbides like TI3SiC2 is
triggered by many researchers.
 Ti3SiC2 is a Ternary Carbide and a thermodynamically
stable laminates, exhibits both Metallic and Ceramic
features.

3. PROPERTIES
High Young’s modulus (325GPa)
Relatively low hardness (4-5GPa)
High fracture toughness (~9MPa m1/2)
High thermal shock resistance.
Good Machinability with conventional tools.
Excellent resistance to oxidation up to 1400°c.

4. STRUCTURE
•Graphite like structure ; has a
hexagonal crystal structure.
•The Ti3SiC2 is a planar stacking
sequence along the c-axis, consisting
of double layers of Ti-C edge sharing
octahedra, sandwiched between
sheets of square planar coordinated Si
atoms.
•It may be thought of as a layered
structure with a c-axis repeat distance
of 1.762 nm and a stacking sequence
consisting of alternating double Ti–C
blocks and Si layers.

5. TRIBOLOGICAL STUDY
 Three major mechanism contributing to the process of
friction and wear of Ti3SiC2
a) Abrasion
b) Tribochemical layer formation
c) Plastic deformation

6. Contd..
Table: The summary of the Friction and wear data obtained
with Ti3SiC2 under varying test condition
D.Sarkar
and B.Basu

7. Contd..
 Myhra et al. Measured a low kinetic friction coefficeint of
0.002 at 25 nN lateral force for the basal planes of Ti3SiC2
, using the LFM (Lateral Force Microscopy).
 They also reported a steady state COF of ~0.12 for a
polycrystalline Ti3SiC2 rubbed against a lightly peened
stainless steel sheet at 0.25-0.9 N load.
 Barsoum measured a steady state COF of around 0.8 in
case of Ti3SiC2/Steel tribocouple under 5N load and
Observed that frictional response is independent of grain
size(5-100um).
 Zhang et al. reported that the friction of self mated Ti3SiC2
tribocouple is ~1.16-1.43 and that of Ti3SiC2/Diamond is
arounf 0.1 under varying loads of 0.98-9.8N.

8. THE FRETTING WEAR OF Ti3SiC2
 The fretting is defined as small amplitude linear relative
tangential sliding at normal constant load.
 An experiment was done by Debasis Sarkar, B.V.
Manojkumar, Bikramjit Basu using a ball on disk type
tribometer and commercial bearing SAE 52100 grade
steel balls (Hardness 63-65HRc) of 8 mm in diameter.
 The fretting wear administrated with varying loads (1-10
N) with constant testing duration , at constant frequency
(8 Hz) and constant displacement stroke (100 μm) at
room temperature.

9. Contd..
Experimental Set up

10. Contd..
Result:
•The evolution of frictional
behaviour was strongly
dependent on normal load as
well as fretting cycles.
•The increase in COF was
due to severe abrasive action
with increase load.
•But a decrease in COF from
0.62 to 0.5 was recorded
when the load was increased
from 6 to 8N and COF remains constant at 10N due to the formation of
tribochemical reaction product and wear debris takes place to a large
extent. These debris particles are entrapped in between the tribocouple
and tends to roll during sliding motion, thereby decrease the friction.

11. R-CURVE
 One among the characteristic material properties for
several of the high toughness ceramics is the enhanced
resistance to crack growth during crack extension , a
phenomena known as ‘R-curve’ behaviour.
 The crack resistance curve of ternary carbides has been
characterized by only Compact Tension (CT) method
(ASTM standard E647).
 Usually in ternary carbides, unlike other ceramics , it is
difficult to introduce initial flaws by any conventional
indentation bridge technique, because of lower hardness
and layered structure. Therefore single edge pre-crack
beam (SEPB) technique is been used to introduce
controlled crack.

12. Contd..
•The fracture mechanism and
characteristic R-curve of
Ti3SiC2 can be explained as
follows;
•Ti3SiC2 is characterized by
relatively weak bonding
between the silicon layer and
the TiC octahedra along the
basal plane.
•The dislocation movement is
restricted to two orthogonal
directions: basal plane and
walls or kink boundaries.
•The delamination along the weaker basal planes results in the creation of
microlaminae contained within a grain and consequently, the deformation
and distortion of such laminae provides a potent contribution to toughening.

13. THANK YOU !