Surface Composite AA6061/SiC Manufactured by Hole and Groove …
135
surface composite manufacturing on the microhardness, wear, and tensile behavior
was also evaluated.
2 Material and Methods
In the current study, AA6061 plates of 120 mm in length, 100 mm in width, and 10 mm
in thickness have been used as the parent metal. The measured chemical composition
of AA6061 is presented in Table 1. The SiC particles with an average particle size of
11 µm were used in this study. The FSP was performed on the conventional vertical
milling machine. Both the hole and groove methods were used to reinforce particles
in the AA6061 surface. In one sample, a total of 60 blind holes of 2 mm × 2 mm size,
with 1 mm horizontal and 2 mm vertical distance among the holes in two rows were
drilled across the plate length at the center. In the other sample, a groove of 1.6 mm ×
2 mm × 120 mm dimension was made at the center of the plate. The surfaces of both
the samples were cleaned, and the dry SiC powder mixed with acetone was applied
in drilled cavities using a brush. Acetone was used as carrier material. Capping pass
was carried out by a pin-less tool to seal the SiC particles on the AA6061 surface,
followed by a stirring pass to distribute the packed particles in the AA6061 matrix,
as displayed in Fig. 1. Conventional En8 heat-treated cylindrical FSP tool having a
22 mm diameter of the shoulder, 5 mm bottom diameter, 3 mm top diameter, and
3 mm length of taper pin, as shown in Fig. 2, was used to produce surface composites.
The processing parameters for FSP were set at tool rotational rate of 1000 RPM, feed
rate of 50 mm/min, and tool tilt angle of 3°.
Specimens for the microstructural study were cut from the stir zone of friction
stir processed samples. Cut specimens were ground using different grinding papers,
polished using the diamond paste, and etched by Keller’s reagent (1% HF, 1.5%
HCL, 2.5% HNO 3 , rest water). The microstructure was studied using a metallurgical
microscope. The cross section microhardness was measured in the stir zone below
1 mm from the top surface at an interval of 1.0 mm using a Vickers microhardness
tester at 300 gm applied load and 10 s dwell. The wear pins were taken from the
stir zone of processed samples. The wear is measured in dry sliding conditions as
per the ASTM G99 standard on a pin-on-disk tribometer. Test parameters were 20 N
load and 1 m/s sliding speed. The tensile specimens were cut as per the ASTM E8
standard, from the manufactured surface composites perpendicular to the processing
direction displayed in Fig. 3. The tensile test was performed on a computerized
universal testing machine.
Table 1 Chemical composition of AA6061
Elements
Al
Mg
Si
Mn
Cu
Zn
Cr
Ti
Weight %
Bal
0.85
0.68
0.32
0.22
0.07
0.06
0.05
135
surface composite manufacturing on the microhardness, wear, and tensile behavior
was also evaluated.
2 Material and Methods
In the current study, AA6061 plates of 120 mm in length, 100 mm in width, and 10 mm
in thickness have been used as the parent metal. The measured chemical composition
of AA6061 is presented in Table 1. The SiC particles with an average particle size of
11 µm were used in this study. The FSP was performed on the conventional vertical
milling machine. Both the hole and groove methods were used to reinforce particles
in the AA6061 surface. In one sample, a total of 60 blind holes of 2 mm × 2 mm size,
with 1 mm horizontal and 2 mm vertical distance among the holes in two rows were
drilled across the plate length at the center. In the other sample, a groove of 1.6 mm ×
2 mm × 120 mm dimension was made at the center of the plate. The surfaces of both
the samples were cleaned, and the dry SiC powder mixed with acetone was applied
in drilled cavities using a brush. Acetone was used as carrier material. Capping pass
was carried out by a pin-less tool to seal the SiC particles on the AA6061 surface,
followed by a stirring pass to distribute the packed particles in the AA6061 matrix,
as displayed in Fig. 1. Conventional En8 heat-treated cylindrical FSP tool having a
22 mm diameter of the shoulder, 5 mm bottom diameter, 3 mm top diameter, and
3 mm length of taper pin, as shown in Fig. 2, was used to produce surface composites.
The processing parameters for FSP were set at tool rotational rate of 1000 RPM, feed
rate of 50 mm/min, and tool tilt angle of 3°.
Specimens for the microstructural study were cut from the stir zone of friction
stir processed samples. Cut specimens were ground using different grinding papers,
polished using the diamond paste, and etched by Keller’s reagent (1% HF, 1.5%
HCL, 2.5% HNO 3 , rest water). The microstructure was studied using a metallurgical
microscope. The cross section microhardness was measured in the stir zone below
1 mm from the top surface at an interval of 1.0 mm using a Vickers microhardness
tester at 300 gm applied load and 10 s dwell. The wear pins were taken from the
stir zone of processed samples. The wear is measured in dry sliding conditions as
per the ASTM G99 standard on a pin-on-disk tribometer. Test parameters were 20 N
load and 1 m/s sliding speed. The tensile specimens were cut as per the ASTM E8
standard, from the manufactured surface composites perpendicular to the processing
direction displayed in Fig. 3. The tensile test was performed on a computerized
universal testing machine.
Table 1 Chemical composition of AA6061
Elements
Al
Mg
Si
Mn
Cu
Zn
Cr
Ti
Weight %
Bal
0.85
0.68
0.32
0.22
0.07
0.06
0.05