8. Advantages
High resistance to fatigue and corrosion.
High resistance to impact damage.
High strength or stiffness to weight ratio.
Less inspections and structural repairs.
Improved friction and wear properties.
9. Disadvantages
High cost of raw materials and fabrication.
Transverse properties may be weak.
Analysis is difficult.
Reuse and disposal may be difficult.
Difficult to attach.
10. Machinability
In general, machinability differs for each material.
But it’s not a material constant.
Machinability depends on machining conditions.
It also depends on the physical and chemical
properties of work part.
12. Parameters of machinability
Mechanical properties of work part,
Cutting tool; material and geometry,
Levels of process parameters,
Machining environment; lubrication, etc.,
Rigidity and stiffness of M/C,
Type of machining operation.
24. Group 1
Drill diameter: 8mm
Speed: 770 RPM (19.35 m/min)
Feed forces: 300, 400, and 500 N
Machining time: 10 sec
Materials:
Base alloy
Al-Si base alloy + 5%wt. Ni
Al-Si base alloy + 10%wt. Ni
Al-Si base alloy + 15%wt. Ni
Al-Si base alloy + 5%wt. Ni + 2%wt 𝐴𝑙2𝑂3
Al-Si base alloy + 5%wt. Ni + 3%wt 𝐴𝑙2𝑂3
26. Group 1
Effect of thrust on consumed power Effect of thrust on penetration depth
27. Group 1
Effect of thrust on feed rate Effect of feed rate on specific cutting resistance
28. Group 2
Drill diameter: 8mm
Speeds: 770, 640, and 480 RPM(19.35, 16.077, 12.058 and
m/min)
Feed force: 400 N
Machining time: 10 sec
Materials:
Base alloy
Al-Si base alloy + 5%wt. Ni
Al-Si base alloy + 10%wt. Ni
Al-Si base alloy + 15%wt. Ni
Al-Si base alloy + 5%wt. Ni + 2%wt 𝐴𝑙2𝑂3
Al-Si base alloy + 5%wt. Ni + 3%wt 𝐴𝑙2𝑂3
30. Group 2
Effect of rotational speed on power Effect of rotational speed on depth
31. Group 2
Effect of feed rate on consumed power Effect of feed rate on specific cutting resistance
32. Group 3 I
Drill diameter: 6mm,
Speed: 640 RPM (12.057 m/min),
Feed force: 300, 400, and 500 N,
Machining time: 10 sec,
Materials:
Base alloy
Al-Si base alloy + 5%wt. Ni
Al-Si base alloy + 10%wt. Ni
Al-Si base alloy + 15%wt. Ni
Al-Si base alloy + 5%wt. Ni + 2%wt 𝐴𝑙2𝑂3
Al-Si base alloy + 5%wt. Ni + 3%wt 𝐴𝑙2𝑂3
40. Conclusion
The machinability of composites is higher than the
base alloy.
Nano
composites
Micro
composites
Base alloy
Machinability decreasing
41. Tensile strength
As the ductility of composites are higher than the base
alloy, it indicates that the machinability of composites
are going to be better than the base alloy.
Material UTS(MPa)
Engineering strain 𝜺
(%)
Base material 296.0 4.8
MMC I 369.7 5.0
MMC II 362.9 5.7
MMC III 310.5 6.0
MMNC IV 390.0 5.9
MMNC V 350 4.4
42. Microhardness
Microhardness of the different specimens was measured
using microhardness tester. The applied load was 100 g.
Specimen 8 1 5 7 3 4
Vickers(HN) 152.33 119.67 145 197 121.33 150