ORIGINAL PAPER

Study of Non-lubricated Wear of the Al–Si Alloy CompositeReinforced with Different Ratios of Coarse and Fine Size ZirconSand Particles at Different Ambient Temperatures

Ranvir Singh Panwar • Suresh Kumar •

Ratandeep Pandey • Om Prakash Pandey

Received: 9 November 2013 / Accepted: 10 April 2014 / Published online: 22 April 2014

� Springer Science+Business Media New York 2014

Abstract In the present work, a detailed study of ceramic

reinforcement of different size ranges in the matrix of

LM13 alloy on the friction and wear behavior has been

carried out. For this purpose, LM13/Zr composite con-

taining 10 wt% zircon sand particles of different size ran-

ges using stir casting process has been developed. Zircon

sand particles were incorporated in two ways: firstly as

single size reinforcement and secondly dual size rein-

forcement. Durability of the composites was tested by

finding the wear rate of the composite against the steel disk

by pin-on-disk method. Addition of zircon sand particles in

the LM13 alloy improves the hardness of the composite as

well as wear resistance. Wear rate of the developed com-

posites was tested under different test conditions by vary-

ing the applied load and ambient temperatures. Wear rate

of the composite changes significantly at different ambient

temperatures. SEM analysis of the worn surfaces was done

to know the operative wear mechanism.

Keywords Metal matrix composites � Hardness � Wear

rate � Temperature

1 Introduction

Composites have become unique materials for most of the

engineering applications [1–3]. Due to improved stiffness,

strength, thermal properties and wear resistance of the

particle-reinforced composites, their applications in several

structural parts particularly where energy consumption is

of primary concern have increased [4, 5]. Moreover, their

properties can be tailored further depending upon request

where an impertinent selection of a certain number of

variables has to be achieved to optimize the properties of

the particle-reinforced composites.

Among the variety of processing techniques available for

particulate-reinforced aluminum matrix composites (PAM-

Cs), stir casting is one of the methods accepted for the pro-

duction of large number of composites [5]. To optimize the

properties of the composites, the shape, size and volume

fraction of the reinforcing particles as well as the matrix

composition have to be chosen carefully. Particulate rein-

forcement by SiC, Al2O3, TiO2, ZrSiO4, Gr, zircoina, etc. has

been selected by many researchers to improve the hardness

as well as wear resistance of the composites [3–9]. Das et al.

[1] have compared the wear properties of alumina- and zir-

con sand-reinforced AMCs and reported that decrease in

particle size improves wear resistance. Zhang and Alpas [10]

suggested that ambient temperature significantly affects the

wear behavior of the materials. It is reported that near the

critical temperature (&0.4 Tm, Tm is the melting tempera-

ture of the materials), wear rate of composites changes sig-

nificantly [8, 10]. There are so many other factors such as

applied load, ambient temperature, sliding velocity, counter

surface, which affect the wear rate of the material. However,

wear behavior of the PAMCs containing different sizes of

zircon sand particles as single size reinforcement (SSR) and

dual size reinforcement (DSR) (in different ratios) has not

been studied systematically.

In our previous work, we have discussed the room

temperature wear behavior of zircon sand-reinforced LM13

composite [4]. It was observed that fine size reinforced

R. S. Panwar � S. Kumar � O. P. Pandey (&)

Metallurgical Research Laboratory, School of Physics and

Materials Science, Thapar University, Patiala 147004, India

e-mail: oppandey@thapar.edu

R. Pandey

Department of Mechanical Engineering, Baba Banda Singh

Bahadur Engineering College (BBSBEC),

Fatehgarh Sahib 140407, Punjab, India

123

Tribol Lett (2014) 55:83–92

DOI 10.1007/s11249-014-0335-y

composites exhibit better wear resistance as compared to

coarse size reinforced composites. However, the segrega-

tion of fine particles has led to variation in structure,

causing wettability problem of particles. In order to sort out

this problem, a combination of fine and coarse size parti-

cles was tried, where the problem of segregation could be

eliminated considerably [4]. The room temperature wear

behavior of DSR composites offered higher wear resistance

as compared to singe size reinforced (SSR) composites [4].

However, high-temperature wear behavior of developed

DSR composites at different applied loads has not been

studied. Considering the need for high-temperature appli-

cations, we have taken this work and studied the high-

temperature wear behavior of the single size reinforced

composites (SSR) and dual size reinforced composites

(DSR), where a sequential addition of fine size zircon sand

was done in DSR composites, keeping the total reinforce-

ment amount constant (10 wt%). This has enabled us to

optimize the proper combination of coarse and fine size

particles in DSR composites for better wear resistance. For

this purpose, we have developed the PAMCs by selecting

the LM13 alloy as matrix and zircon sand (ZrSiO4) as

reinforcement. PAMCs are developed by stir casting route.

Different sizes (coarse and fine size) of zircon sand parti-

cles were chosen to study the effect of particle size on the

wear behavior of the composites. For better understanding

the effects of particle size in the matrix, SSR and DSR

were incorporated in the LM13 alloy. However, coarse and

fine size particles in different ratios were incorporated in

the LM13 alloy matrix to get better idea on wear behavior

of DSR composites. Wear behavior of the developed

composites was studied at different testing conditions with

varying the applied loads and ambient temperatures.

2 Experimental Details

2.1 Materials Used

In this study, well-known piston alloy LM13 (Al–12Si–3Mg)

was used as matrix material and high-purity zircon sand

(ZrSiO4) as reinforcement. LM13 alloy was obtained in the

form of ingots from Emmes Metal Pvt. Ltd., Mumbai. Fine

(20–32 lm) size and coarse (106–125 lm) size of zircon sand

particles were used to study the effect of particle size on the

wear behavior of the materials. The compositional analysis of

the LM13 alloy is given in Table 1. Table 2 gives the com-

position of zircon sand used in the present work.

2.2 Development of the Composites

For the development of the composites, LM13 alloy ingots

were first melted in an electric furnace at 800 �C and held

at 750 �C in a graphite crucible. The melt was stirred with

a graphite stirrer containing three blades. During stirring,

speed was increased continuously till vortex was created,

which is the best condition for the homogeneous mixing of

the particles in the matrix [6]. At 630 rpm, after creating

the vortex in molten metal, 10 wt% zircon sand particles

were incorporated with the help of funnel kept at the top of

crucible. Stirring of the molten mass was done for around

10 min to get the homogeneous distribution of particles in

the matrix. After stirring, molten mass was poured in the

cast iron mold of 12 9 12 9 4 cm3 dimensions and

allowed to cool in air at room temperature. From these

developed particles-reinforced aluminum matrix compos-

ites, samples were prepared for further characterization.

Two main categories of the composites were prepared: (1)

SSR, which contains only coarse (SSR-1) and fine (SSR-2)

size of particles as reinforcement, and (2) DSR, which

contains a combination of coarse and fine size particles in

different ratios. Table 3 shows the classification of the

developed composites reinforced with coarse and fine size

particles.

The bulk hardness of the LM13 alloy and LM13/Zircon

sand composite was measured by Rockwell hardness tester

(Model: TRSND) using 1/1600 diameter steel ball indenter

Table 1 Chemical composition of the LM13 alloy

LM13 alloy Si Fe Cu Mn Mg Zn Ni Al

Wt% 12 0.3 1.2 0.4 3.0 0.2 0.9 Bal

Table 2 Chemical composition of the zircon sand (ZrSiO4)

Elements ZrO2 (?HfO2) SiO2 TiO2 Fe2O3

% in bulk 65.30 32.80 0.27 0.12

Table 3 Classification of the developed composites containing zir-

con sand particles of different sizes

SSR composites DSR

composite

Amount of particles in

the matrix (10 wt%)

Ratio of coarse and fine

size particles in the

matrix [coarse

(106–125 lm) : fine

(20–32 lm)]

Composite Amount and size

of reinforced

particles

SSR-1 10 wt% with

coarse

(106–125 lm)

size

DSR-10A 4:1

DSR-10B 4:2

SSR-2 10 wt% with

fine

(20–32 lm)

size

DSR-10C 2:4

DSR-10D 1:4

84 Tribol Lett (2014) 55:83–92

123

under 100 kgf load at B scale. A fine manufacturing

industry, India make Rockwell hardness tester (Model:

TRSND) was used for carrying out the hardness test.

Durability of the composites was analyzed by the wear

test. For the wear test, cylindrical specimens of 8 mm

diameter and 40 mm length were machined from the stir

cast composites. Wear testing was performed on pin-on-

disk wear and friction monitor (Model TR-20, Ducom,

Bangalore, India) under dry sliding conditions in ambient

air. Figure 1a–c shows different parts of the wear and

friction monitor. The machine consists of three units as

shown in Fig. 1. The first unit consists of a chamber in

which the rotating disk exists. This is derived by a motor

fitted beneath it. The chamber is heated by three band

heaters fixed along the walls as shown in Fig. 1a, b. To

measure the temperature, the thermocouple is fitted inside

the chamber as shown in Fig. 1b. The pin is tightly fixed in

the sample holder before the start of the test. The load on

the pin is applied through the sample holder connected

through steel wire as shown in Fig. 1c. After all the

adjustments, the chamber was covered from top to check

the heat loss. The top cover also contains insulating bricks.

During operation of machine, the data were collected in

computer as shown in Fig. 1c. The display monitor con-

tinuously shows the variation during the test (Fig. 1c).

Effect of applied load was observed by varying the load

from 9.8 to 49 N. To get the effect of ambient temperature on

the wear behavior of the composites, wear tests were con-

ducted at 50, 100, 150, 200, 250 and 300 �C with 9.8 and

49 N loads. All the developed composites and base alloy

were tested at a constant speed of 1.6 m/s against EN 32 steel

disk having hardness 65 HRC. Wear tests were performed

under the ambient temperatures between 25 and 30 �C (room

temperature) and at relative humidity between 25 and 35 %.

To get an average value of wear rate, each test was run three

times. Before each test, the track was cleaned with acetone.

Wear rate was determined by measuring specimen height

change using a linear variable displacement transducer

(LVDT). To study the wear behavior, wear rate was calcu-

lated by using the formula, [W (mm3/m) = height change

(mm) 9 pin area (mm2)/sliding distance (m)]. Specific wear

rate, k (mm3/Nm), was calculated by the wear rate at the

particular applied load (N). To get a better idea about the

wear mechanism during the wear tests in different condi-

tions, wear tracks of some selected composite materials were

studied with the help of SEM (JOEL, JSM-6510LV).

3 Results and Discussion

3.1 Hardness

The hardness of the composites and the base alloy is shown

in Fig. 2. It shows that hardness of the composites

increases with the addition of zircon sand particles in the

base alloy. However, both SSR-1 and SSR-2 composites

containing coarse and fine size zircon sand particles,

respectively, show improved hardness in comparison with

the base alloy. Higher hardness of SSR-2 composite is

because of the dispersion of fine size particles in larger area

in the matrix. Our previous study [6] shows that zircon

sand particles react at interface and make a good bond by

forming Al2SiO5 at the interface. The improvement in

hardness of the composites is because of the Al2SiO5 and

more number of zircon sand particles. On the other hand in

DSR composites, hardness also varies with the change in

ratio of coarse and fine size reinforcement (Fig. 3). DSR-

10D composite shows the highest hardness in comparison

with the other developed DSR composites though the

variation is little.

Fig. 1 The image of the wear and friction monitor showing different

parts: a top view of wear test machine, b top view of steel disk and

schematic diagram of pin sample and steel disk with wear track and

c front view of wear test machine

Tribol Lett (2014) 55:83–92 85

123

3.2 Wear Test

3.2.1 SSR Composites

3.2.1.1 Effect of Applied Load on the Wear Behav-

ior Graphs presented in Fig. 4a–c show the variation in

wear rate of the base alloy as well as SSR-1 and SSR-2

composites at different load conditions. Graphs plotted

between wear rate and sliding distance at different loads

show that wear rate of the base alloy, SSR-1 and SSR-2

composites increases with increasing the applied load.

However, two stages of the wear rate behavior are

observed: first is steep change in wear rate up to around

1,500 m of sliding distance and second exhibiting steady

change in wear rate after 1,500 m. This variation in the

wear rate with sliding distance is due to change in run in

wear condition to steady state. This steady state of wear

rate is achieved by the material after acquiring constant

temperature between the surfaces of the sample and

counter surface of steel disk. However, when increasing the

Har

dn

ess

(HR

B)

0

5

10

15

20

25

30

35

40

45

50

Base LM13 alloy

Material

SSR-1 SSR-2

Fig. 2 Hardness of the base alloy and SSR composites containing

zircon sand particles of different sizes

DSR-10A DSR-10B DSR-10C DSR-10D0

5

10

15

20

25

30

35

40

45

50

Har

dn

ess

(HR

B)

DSR composite

Fig. 3 Hardness of the DSR composites containing different ratio of

coarse and fine size zircon sand particles

5

10

15

20

25

30

35

40

Wea

r ra

te x

10-3

( mm

3/m

)

Sliding distance (meter)

9.8 N 19.6 N 29.4 N 39.2 N 49 N

(a)

0

2

4

6

8

10

12

14

16

18

20

22

wea

r ra

te ×

10-3

(mm

3/m

)

Sliding distance (meter)

9.8 N 19.6 N 29.4 N 39.2 N 49 N

(b)

500 1000 1500 2000 2500 3000

500 1000 1500 2000 2500 3000

500 1000 1500 2000 2500 30000

2

4

6

8

10

12

14

16

9.8 N 19.6 N 29.4 N 39.2 N 49 N

Wea

r ra

te ×

10

-3(m

m3/m

)

Sliding distance (meter)

(c)

Fig. 4 Wear rate against sliding distance at different loads for a base

alloy, b SSR-1 and c SSR-2

86 Tribol Lett (2014) 55:83–92

123

load from 39.2 to 49 N, a severe change in wear behavior is

observed. SSR-1 and SSR-2 composites show better wear

resistance in comparison with base LM13 alloy.

3.2.1.2 Effect of Ambient Temperature on the Wear

Behavior Wear behavior of the material is significantly

affected by the ambient temperature during the wear tests.

To study the effect of ambient temperature, wear tests were

carried out from 50 to 300 �C at low (9.8 N) and high

(49 N) loads. Figure 5 shows the effect of different ambi-

ent temperatures at 9.8 and 49 N loads on the wear rate of

base LM13 alloy, SSR-1 and SSR-2 composites. Figure 5

clearly indicates improvement in the wear rate of the LM13

alloy after the addition of zircon sand particles as rein-

forcement for all the temperature ranges at 9.8 and 49 N

loads.

Figure 5a shows the wear behavior of base alloy and

composites at different temperatures for low load (9.8 N). It

was observed that the wear rate for the both base alloy and

composites (SSR-1 and SSR-2) decreases with increasing

the temperature from 50 to 200 �C. The minimum wear rate

observed was around 200 �C due to the formation of pro-

tective oxide layer on the surface of pin [11]. Zhang and

Alpas [10] suggested that there is a critical transition tem-

perature in an alloy around *0.4 Tm (Tm is melting tem-

perature of alloy). For LM13 alloy, critical temperature is

around 250–260 �C. They suggested that at this critical

temperature, material undergoes softening adjacent to the

contact surfaces and thermally activated deformation pro-

cess occurs, which leads to the increase in wear rate at higher

temperatures. Wilson and Alpas [11] suggested that these

oxide layers at higher temperature (around 200 �C) reduce

the wear rate by avoiding direct metal-to-metal contact

between the surfaces of specimen and steel disk. Above

200 �C (nearly 0.4 Tm), thermally activated deformation

occurs and wear rate of the materials increases due to tearing

of the oxide layers which provide new area for the wear.

Hence, wear rate of the material increases significantly at

higher temperature (300 �C). Both base alloy and compos-

ites show similar wear behavior at different ambient tem-

peratures, but composites show improved wear resistance in

comparison with the base alloy. However, due to low applied

load, effect of particle size for SSR-1 and SSR-2 composites

on the wear rate is not considerable. Both the composites

show similar wear behavior at low load (9.8 N).

Figure 5b shows the variation in the wear rate for the base

alloy, SSR-1 composite and SSR-2 composites at higher load

(49 N). For the base alloy, wear rate increases sharply with

increasing the temperature from 50 to 150 �C. However, at

much higher temperature (from 200 to 300 �C) in presence of

higher load (49 N), base alloy was worn out. In this condi-

tion, a massive removal of materials was observed, which

leads to high wear rate. In the presence of higher load, wear

rate of the SSR-1 and SSR-2 composites increases with

increasing the ambient temperature from 50 to 150 �C.

However, around 200 �C due to the formation of oxide layer,

wear rate of both the composites decreases. At 250 �C, wear

rate of both composites increases due to the tearing of oxide

layers at higher temperatures. The tearing of oxide layers

exposes new area to delaminate during the wear test. This

exposed surface further undergoes oxidation. The formation

of oxide layer at higher temperatures and at higher loads is

very fast. After sometime, an equilibrium is achieved, and

the debris generated during this process forms mechanically

mixed layer (MML) on the surface of the pin, which protects

the surface from further oxidation. At 300 �C, wear rate of

the composites (SSR-1 and SSR-2) again decreases in the

presence of higher loads (49 N). Wilson and Alpas [11]

suggested that around 300 �C at high loads, there may be

generation of debris within steel disk. This debris transfers to

the opposing surface of the composite and forms MML. This

MML further leads to the decrease in the wear rate of the

composites.

50 100 150 200 250 3000

1

2

3

4

5

6

7

8W

ear

rate

× 1

0-3(m

m3/m

)

Temperature (°C)

Base SSR-1 SSR-2

(a)

50 100 150 200 250 3000

3

6

9

12

15

18

21

24

Wea

r ra

te ×

10

-3(m

m3/m

)

Temperature (°C)

Base SSR-1 SSR-2

(b)

Fig. 5 Comparison of wear rate against temperature for base alloy

and composites at a 9.8 N and b 49 N

Tribol Lett (2014) 55:83–92 87

123

3.2.1.3 Effect of Applied Load on the Specific Wear Rate of

the Base Alloy and Composites Figure 6 shows a com-

parison of specific wear rate of the both base alloy and SSR

composites against applied normal stress. Applied normal

stress was calculated by using Hertz theory [contact

pressure P (N/m2) = 3/2 (F/pa2), where ‘F’ is applied

force (N) and ‘a’ is the contact radius (m)] [12]. Here, we

have prepared cylindrical pin with flat surface (ground at

1,200 grit emery paper) of both base alloy and composites.

For more significant data values, error bars have been

incorporated in the graphs. It was observed that with the

increase in the applied normal stress, specific wear rate of

base alloy and composite decreased. At higher applied

normal stresses, deformation resistance of SSR increases

with decreasing particle size of the reinforcement.

3.2.2 DSR Composites

3.2.2.1 Effect of applied load on the wear behav-

ior Figure 7a–d shows the wear behavior of the dual size

reinforced composites DSR-10A, DSR-10B, DSR-10C and

DSR-10D, respectively. Figure 7 shows the wear behavior

of the composites at different sliding distances in the pre-

sence of different applied loads varying from 9.8 to 49 N.

Similar wear behavior was observed with the dual size

reinforcement (DSR) composites as that of single size

reinforcement (SSR) composites. All the DSR composites

show run in wear condition in the initial stage and a steady

state in later stage. For DSR-10A composite which

0.072 0.144 0.216 0.288 0.3600.0

0.1

0.2

0.3

0.4

0.5S

pec

ific

wea

r ra

te (

mm

3/N

m)

Applied normal Stress (Mpa)

LM13 alloy SSR 1 SSR 2

Fig. 6 Specific wear rate against applied normal stress for base alloy

and SSR composites

0

2

4

6

8

10

12

14

16 9.8 N 19.6 N 29.4 N 39.2 N 49 N

Wea

r ra

te ×

10

-3(m

m3/m

)

Sliding distance (meter)

(a)

0

2

4

6

8

10

12

14

16 9.8 N 19.6 N 29.4 N 39.2 N 49 N

Wea

r ra

te ×

10

-3(m

m3/m

)

Sliding distance (meter)

(b)

0

2

4

6

8

10

12

14

16

9.8 N 19.6 N 29.4 N 39.2 N 49 N

Wea

r ra

te ×

10

-3(m

m3/m

)

Sliding distance (meter)

(c)

500 1000 1500 2000 2500 3000

500 1000 1500 2000 2500 3000

500 1000 1500 2000 2500 3000

500 1000 1500 2000 2500 30000

2

4

6

8

10

12

14

16 9.8 N 19.6 N 29.4 N 39.2 N 49 N

Wea

r ra

te ×

10

-3(m

m3/m

)

Sliding distance (meter)

(d)

Fig. 7 Wear rate against sliding distance at different loads for a DSR-10A, b DSR-10B, c DSR-10C and d DSR-10D

88 Tribol Lett (2014) 55:83–92

123

contains coarse and fine size zircon sand particles in ratio

4:1, wear resistance is lower in comparison with all other

DSR composites. However, the composition of 1:4 ratio of

coarse and fine size particles in matrix, i.e., DSR-10D

composite shows better wear resistance in comparison with

other DSR composites. It was observed that wear resistance

of the DSR composites improved with increasing amount

of fine size particles. However, wear rate of all the DSR

composites increases with increasing the applied load on

the materials.

Combination of fine and coarse size particles exhibits

better wear resistance as fine particles affect the larger area

to improve hardness and coarser particles help in bearing

the higher loads. Hence, at high load conditions, DSR-10D

composite shows better wear resistance.

3.2.2.2 Effect of Ambient Temperatures on the Wear

Behavior Figure 8a, b shows the effect of different

ambient temperatures on wear rate of the composite in the

presence of low (9.8 N) and high (49 N) loads, respec-

tively. DSR composites also show similar behavior to SSR

composites at different ambient temperatures and at dif-

ferent applied loads. Moreover, DSR composites show

better wear resistance in comparison with the SSR com-

posites. Figure 8a shows decrease in the wear rate with

increasing the ambient temperature from 50 to 150 �C at

low (9.8 N) load. This is due to the wedging of particles in

softened matrix, which supports the better wear resistance

at low load. At around 200 �C, due to the formation of

oxide layers between the participating surfaces, wear rate

of the composites decreases sharply [11]. However, at

much higher temperatures (at 250 and 300 �C), tearing of

oxide layers at low loads exposes new area for wearing

during the continuous rubbing of surfaces and results in

higher wear rates. However, it was observed that DSR-10D

composite shows better wear resistance in comparison with

the other DSR composites for all the ambient temperatures

and loads.

Figure 8b shows the wear rate of the DSR composites at

high (49 N) loads at different ambient temperatures. Wear

rate of the DSR composites is improved with the increase

in fine size particles content as compared to the coarser size

particles in the matrix. DSR-10D shows better wear resis-

tance at all conditions as compared to other DSR com-

posites. At high loads (49 N), wear rate of the composite

increases with increase in the temperature from 50 to

150 �C. However, due to formation of oxide layer at

around 200 �C, wear rate of all the DSR composites

decreases sharply, as oxide layers stave off the contact

between the sliding surfaces of specimen and steel disk. At

much higher temperatures (250 �C) and due to continuous

rubbing of surfaces at high loads, oxide layers got damaged

and exposed new area for the delamination or wear, hence,

wear rate of the material increases again. At 300 �C,

transfer of steel debris from counter surface to specimen

occurs, which helps in the formation of MML and

improves the wear resistance of the composite in this

condition [11].

3.2.2.3 Effect of Dual Size Reinforced Particles Ratio on

the Wear Behavior Ratio of dual size reinforced particles

in the matrix affects the wear rate of the composites sig-

nificantly. Figure 7 shows the change in wear rate with

variation in coarse and fine size ratio of the particles in the

matrix. Figures 7, 8 and 9 reveal that wear resistance of the

composites improves with increasing the content of fine

size particles in DSR composites. DSR-10D composite

with the ratio of 1:4 of coarse and fine size particles shows

better wear resistance in comparison with all other DSR

composites. A proportionate combination of coarse and

fine size particles in the matrix provides enhanced

mechanical and tribological properties of the composites.

50 100 150 200 250 3001

2

3

4

5

6

7

8W

ear

rate

× 1

0-3(m

m3

/m)

Temperature (°C)

DSR 10A DSR 10B DSR 10C DSR 10D

(a)

50 100 150 200 250 3002

3

4

5

6

7

8

9

10

11

12

Wea

r ra

te ×

10-3

(mm

3/m

)

Temperature (°C)

DSR 10A DSR 10B DSR 10C DSR 10D

(b)

Fig. 8 Comparison of wear rate against temperature for base alloy

and composites at a 9.8 N and b 49 N

Tribol Lett (2014) 55:83–92 89

123

Due to larger effective area of fine particles in the matrix,

DSR composites exhibit higher hardness, while the pre-

sence of coarser size particles in the matrix provides good

resistance to wear at higher load.

Figure 9 shows the change in specific wear rate (mm3/

N m) against the applied normal stress (MPa) of the DSR

composites. It indicates that specific wear rate of com-

posites improves with decreasing the particle size of the

reinforcement. However, a particular ratio of coarse and

fine size particles (1:4) in matrix (DSR-10D composites)

provides better wear resistance at all the loads as compared

to other DSR composites. The increase in fine size particle

content in DSR has improved the wear resistance. At par-

ticular ratio (DSR-10D composites), fine size particle

works as a mediator for transferring the normal stress to

coarse particle in the composite materials and helps in

improving the wear resistance.

3.3 Topographical Analysis of the Wear Tracks

Topographical study of the worn surface of the composites

renders the mechanism involved during the wear test at

different conditions. For this purpose, worn surfaces of the

composites were exploited by analyzing them under scan-

ning electron microscope. As all the developed composites

show similar type of wear behavior, we have chosen the

worn surfaces of the composites exhibiting better wear

resistance at higher loads and at higher temperatures. We

have studied the worn surfaces of the composites tested at

higher loads (49 N) and at higher temperatures for the

SSR-1, SSR-2 and DSR 10D composites. Figure 10a–c

shows the wear tracks of the SSR-1, SSR-2 and DSR-10D

composites tested at 200 �C with 49 N load, respectively.

The presence of high loads and high temperatures supports

the higher wear rate of the composites. Worn surface of

SSR-1 composites shows the formation of continuous

abrasive grooves along with delaminated area (Fig. 10a).

Due to the entrapment of hard zircon sand particles

between the sliding surfaces of composite and steel disk,

grooves are generated, which are in the direction of sliding

[8]. The parallel and continuous scratches point out the

abrasive wear, which is due to the penetration of the hard

zircon sand particles into the softer surface. Observed

damaged area is due to flow of materials along the sliding

Fig. 10 SEM images of the wear tracks collected at 200 �C and

49 N load for a SSR-1 composite, b SSR-2 composite and c DSR-

10D composite

0.072 0.144 0.216 0.288 0.3600.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40S

pec

ific

wea

r ra

te (

mm

3/N

m)

Applied normal stress (MPa)

DSR 10A DSR 10B DSR 10C DSR 10D

Fig. 9 Specific wear rate against applied normal stress at different

applied load with different ratio of dual size reinforced particles in the

matrix

90 Tribol Lett (2014) 55:83–92

123

direction and tearing of the surface at higher loads. Fig-

ure 10a–c reveals that depth of grooves decreases with

decreasing the particle size, and larger delaminated area

was observed for the higher wear rate of the material.

Wavy patterns observed in Fig. 10a–c indicate the presence

of adhesive wear, which is due to softening of the com-

posite at higher temperatures.

Figure 11a–c shows the wear tracks of the SSR-1, SSR-

2 and DSR-10D composites tested at 250 �C with 49 N

load, respectively. Presence of deeper abrasive grooves and

larger delaminated area indicates the higher wear rate in

the testing condition. Deeper abrasive as well as adhesive

grooves indicates that higher ambient temperatures make

the matrix soft. Larger damaged area due to chipping out of

the material at higher loads and at higher temperatures is

also an indication of higher material loss. This larger del-

aminated area indicates the adhesive wear that dominates

in this testing condition. Sudarshan and Surappa [13]

suggested that the void nucleation around particles in the

deformed region and their subsequent growth and their

linkage parallel to surfaces lead to the delamination of the

specimen surface. Due to higher temperatures, the higher

degree of softening of surface materials and partial melting

of worn surface along with the adhesion between com-

posite surface and steel disk are responsible for the mild to

severe wear transition of the composites, which is also

observed in Figs. 5b and 8b. Hence, higher load and higher

temperature conditions during the wear test enhance the

wear rate of the composite significantly.

4 Conclusions

In the present work, the effect of single and dual size

reinforced particles on wear behavior of LM13/Zircon sand

composite was studied at different ambient temperatures

and loads. Results of the study are summarized as:

1. Hardness of the Al–Si alloy was improved with the

addition of zircon sand particles. However, composite

with finer size particles (SSR-1) shows better hardness

in comparison with the SSR-2 composite.

2. A particular ratio of coarse and fine size zircon sand

particles in the matrix (DSR-10D) shows better

hardness in comparison with all other developed

composites.

3. Wear resistance of the Al–Si alloy was improved with

the addition of zircon sand particles.

4. DSR composites show better wear resistance at low

and high load conditions and also at different ambient

temperatures as fine size particles improve the hard-

ness of the material and coarse size particles support

better load transfer from the matrix to reinforcement

materials.

5. DSR-10D composite shows better wear resistance in

comparison with all the developed SSR and DSR

composites for all testing conditions.

6. Ambient temperature plays an important role for the

wear mechanism at different load conditions, as

formation of oxide layer around 200 �C decreases the

wear rate of the composites and at much higher

temperatures wear rate increases significantly due to

damage of the oxide layers.

Fig. 11 SEM images of the wear tracks collected at 250 �C and

49 N load for a SSR-1 composite, b SSR-2 composite and c DSR-

10D composite

Tribol Lett (2014) 55:83–92 91

123

7. Both abrasive and adhesive wear mechanisms were

observed in SEM analysis of the worn surfaces.

Acknowledgments The authors are thankful to Armament Research

Board (ARMREB), Defence Research and Development Organization

(DRDO), India, for providing financial support under the Letter No.

ARMREB/MAA/2008/105 for this study.

References

1. Das, S., Das, S., Das, K.: Abrasive wear of zircon sand and

alumina reinforced Al–4.5 wt% Cu alloy matrix composites—a

comparative study. Compos. Sci. Technol. 67, 746–751 (2007)

2. Hosking, F.M., Folgar, F.P., Wunderlin, R., Meharbian, R.:

Composites of aluminium alloys: fabrication and wear behavior.

J. Mater. Sci. 17(2), 477–498 (1982)

3. Dwivedi, D.K.: Adhesive wear behavior of cast aluminium–sili-

con alloys: overview. Mater. Des. 31, 2517–2531 (2010)

4. Kumar, S., Sharma, V., Panwar, R.S., Pandey, O.P.: Wear

behavior of dual particle size (DPS) zircon sand reinforced alu-

minum alloy. Tribol. Lett. 47, 231–251 (2012)

5. Hashim, J.: The production of cast metal matrix composite by a

modified stir casting method. J. Teknologi 35(1), 9–20 (2001)

6. Panwar, R.S., Pandey, O.P.: Study of wear behavior of zircon

sand-reinforced LM13 alloy composites at elevated temperatures.

J. Mater. Eng. Perform. 22, 1765–1775 (2013)

7. Mazaheri, Y., Meratian, M., Emadi, R., Najarian, A.R.: Com-

parison of microstructural and mechanical properties of Al–TiC,

Al–B4C and Al–TiC–B4C composites prepared by casting tech-

niques. Mater. Sci. Eng. A 560, 278–287 (2013)

8. Panwar, R.S., Pandey, O.P.: Analysis of wear tracks and debris of

stir cast LM13/Zr composite at elevated temperatures. Mater.

Charact. 75, 200–213 (2013)

9. Martinez, M.A., Martin, A., Llorca, J.: Wear of SiC-reinforced

Al-matrix composites in the temperature range 20–200 �C. Wear

193, 169–179 (1996)

10. Zhang, J., Alpas, A.T.: Transition between mild and severe wear

in aluminum alloys. Acta Mater. 45, 513–528 (1997)

11. Wilson, S., Alpas, A.T.: Effect of temperature on the sliding wear

performance of Al alloys and Al matrix composites. Wear 196,

270–278 (1996)

12. Johnson, K.L.: Contact mechanics, pp. 92–93. Cambridge Uni-

versity Press, New York (1985)

13. Sudarshan, Surappa, M.K.: Dry sliding wear of fly ash particle

reinforced A356 Al composites. Wear 265, 349–360 (2008)

92 Tribol Lett (2014) 55:83–92

123