major conclusions of the present study on density, hardness, tensile strength,
microstructure, dry sliding wear and abrasive wear behavior of metal matrix composites
and hybrid metal matrix composites are summarized below.
The density of composites increased with
increasing in content of wt. percentage of silicon carbide and alumina
The density of composites increased with
increasing mesh size of silicon carbide particle.
The hardness of composites increased
with increasing in content of wt.
fraction and mesh size of silicon carbide particle.
The ultimate tensile strength of
composites increased in content of 30 wt. percentage and mesh size of silicon
6.2 DRY SLIDING WEAR BEHAVIOUR OF
Al6061T6/ SiC MMCs
For different reinforcement (5% up to
40%) & mesh size (150 and 600) of SiC particulates with Al6061 metal matrix
composite has a marked effect on the wear rate. The wear rate decreases with
increasing weight percentage of reinforcement for both the particle mesh size
Coefficient of friction decreases
linearly with increasing reinforcement of SiC and applied load respectively for
both the particle mesh size of SiC composites.
Wear rate increases with increasing
applied load and sliding distance for both the particle mesh size of SiC
Mesh size of SiC particle play vital role in
the Al MMCs which influencing the wear rate and coefficient of friction.
The best result has been obtained at 35%
weight fraction & 600 mesh size of SiC particle in case of wear rate and
coefficient of friction.
6.3 DRY SLIDING WEAR BEHAVIOUR OF Al6061/10% SiC and Al6061/10% SiC MMCs
USING TAGUCHI’S TECHNIQUE
Orthogonal array was used to optimize the multiple
performance of dry sliding wear characteristics of aluminium composites.
Based on the ANOVA results, it is observed that sliding
distance (62.5%) has the highest influence on wear rate followed by sliding
speed(37.5%) and applied load (1.25%) and for coefficient of friction, the
contribution of applied load is 85.5%, sliding distance is 13.4% for Al –
6061/ 10% SiC metal matrix composites.
ANOVA results observed that applied load (57.2%) has
the highest influence on wear rate followed by sliding distance (7.1%) and
sliding speed (7.1%) and for coefficient of friction, the contribution of
applied load is 87.2%, sliding distance is 9.7% for Al – 6061/ 15% SiC
metal matrix composites.
Increasing incorporation of SiC (10% & 15%)
increases the wear resistance of composites by forming a protective layer
between pin & counterface.
From the above conclusion we predict that sliding
distance & applied load have the highest influence on wear rate in both
Similarly applied load is only parameter which is
largely influence the coefficient of friction in both composites.
Regression equation generated for the (10% & 15%
SiC MMCs) present model was used to predict the wear rate & coefficient of
friction of Al – 6061/(10% & 15%) SiC MMCs for intermediate conditions with
Confirmation experiment was carried out & made a
comparison between experimental values showing an error associated with dry
sliding wear & coefficient of friction in both composites varying from
4.69% to 11.23% and 3.17% to 9.256% respectively. Thus design of experiments by
Taguchi method was successfully used to predict the tribological behavior of
6.4 DRY SLIDING WEAR BEHAVIOUR OF Al6061/15% SiC/ 15% Al2O3
HMMCs USING TAGUCHI’S TECHNIQUE AND
GREY RELATIONAL GRADE
An orthogonal array with Grey Relational
Analysis was used to optimize the multiple performance of dry sliding characteristics
of aluminium hybrid composites.
Based on the ANOVA, it is observed that
sliding distance (37.42%) has the highest influence on tribological behaviour
followed by applied load and sliding speed. The interaction set of parameters
have less influence on friction and wear property of hybrid composite.
From the Taguchi analysis the optimal
combination of process parameter for minimum wear and friction is found to be
L3S1D3, i.e., the highest level of sliding distance and applied load along with
lowest level of sliding speed.
Wear depth is reduced by 40.47% from
initial to optimal process parmeter condition and friction is slight decreased
Incorporation of SiC and Al2O3
particulate increase the wear resistance of hybrid composites by performing a
protective layer between pin and counterface. It has a significant effect on
the friction and wear depth.
Confirmation test was carried out and
made a comparision between initial and optimal experimental parameter values
which shows wear depth is reduced by 40.47% and friction is slightly decreased
From the microstructure study of worn
surfaces, it is observed that mostly abrasive wear mechanism has occurred on
FOR FUTURE WORK
The scope of present work can be expended by
including the following areas for future research work.
Investigations to be carried out for different
reinforcement like boron carbide and tungsten carbide with different particle
size, weight fraction of reinforcement, high temperature to obtain optimal wear
behavior of hybrid aluminium composites. Other fabrication techniques such as
squeeze casting and powder metallurgy methods could be tried and analyzed.
An effort to fabricate real components like piston,
cylinder, connecting rods and other applications where sliding contact is
expected and testing the same to evaluate the application potential of the
The fabricated real composites have to be heat
treated to explore maximum possible properties of the composites and test have
to be conducted at different heat treatment conditions for composites.
An effort to evaluate the optimal parameter of wear behavior
could be tried by other optimization techniques such as artificial neural
Machinability study could be conducted, to study the
tool life, cutting force, surface roughness of the hybrid composites.