Aluminium alloys are widely used in aerospace automobile industries due to their low density and good mechanical properties, better corrosion resistance and wear, low thermal coefficient of expansion as compared to convention metals and alloys.

1. DEPARTMENT OF METALLURGICAL
ENGINEERING
G.I.E.T, GUNUPUR -765022
PROJECT BY
JITENDRA MAHARANA

2. PROJECT
ON
“STUDY THE MECHANICAL BEHAVIOR
OF Al 7075 ALLOY BASED COMPOSITES
BY HOT COMPRESSION”

3. INTRODUCTION
• The Al 7075 alloy is a very interesting material because of its
mechanical properties namely-
 Lowdensity
 High strength
 Moderate ductility
 Toughness
Due to these properties, the alloy is mainly used for highly stressed
structural parts. This material has a wide range of application such as
–
 Air craft fittings
 gears and shafts
 fuse parts
 meter shafts and gear
 missile parts
 regulating valve parts
 worm gears
 keys and various other parts of commercial aircraft
 And aerospce vechicles
•

4. What is composite?
• A composite is a material having two or more distinct
constituent or phase.
Ex-concrete and naturally occuring composite like
bone, wood etc .

5. What is metal matrix composite?
MMC is a composite material with at least two
constituents parts, one being a material necessarily, the
other material may be a different metal or another
material, such as a ceramic or organic compound.

6. CURRENT STATUS OF WORK:
• Microstructure of base alloy 7075

7. 2. Chemical Composition:-
Si- 0.40%
Mg- 2.1-2.9%
Cu- 1.2-2.1%
Zn- 5.1-6.1%
Density- ρc × vc = ρm × vm + ρf × vf
Density- 2.8gm/cc
3. Properties:-
Melting point - 483°C
Tensile strength – 220Mpa
Yield strength – 91Mpa
Thermal conductivity – 130w/m-k

8. OBJECTIVES:
 The main objective of our project work is to improve the
mechanical property of the material through plastic
deformation.
 Plastics deformation techniques are-
1.Hot rolling/Hot forging
2.Hot compression
HOT COMPRESSION:
 The compression test specimens were machine to have
cylindrical shape with 7mm diameter and 8.4mm height.
 Carbon powder was used as a lubricant to decrease the
effect of friction and barreling.

9.  The deformation temperature and strain rate were
automatically control by the machine control unit.
 The experimental temperatures were between 250 and
450ºc with an interval of 50ºc.
 At each deformation temperature four constant strain
rate were applied(0.002,0.02,0.2 and 2 s ˉ)
STRENGTHENING
MECHANISM:
 Recovery
 Recrystallization
 Grain growth

10. RECOVERY
 It is a low temperature phenomena which result in
the restoration of physical properties.
 In this region, no appreciable change in
microstructure is observed.
 The grains remain distorted and hence mechanical
properties such as hardness, tensile strength and
ductility do not change appreciably.
 Negligible effect on hardness
 Release internal stresses
 Reduce the number of dislocation
 However, due to heating, some imperfection like
vacancies and interstitialcies exiting in the slip
bands may get eliminated.

11. RECRYSTALLIZATION
 In this region old distorted grains are replaced by
new stress free grain, strain free grains by a
process of neucleation and growth This occurs by a
recrystallization process.
 The microstructure at the end of recrystallization
process is very much similar to the original structure
i.e similar to the structure prior to cold work.
 The grains become equiaxed and the dislocation
density gets reduced to a value characteristics of
strain free metal.
 Due to change in microstructure, all the mechanical
properties are changed and the internal stresses are
reduced.

12. GRAIN GROWTH
 If a completely recrystallized material is heated to a
higher temperature and kept for a longer time at the
annealing temperature, it will show that the size of
the grain will increases.
 It affects on the ductility of the material i.e the
ductility will be improved.
 During this type of growth, some grains grow
abnormally at the expense of the surrounding
recrystallized grains.
 This occurs by rapid migration of grain boundaries
of few of the primary recrystallized grains with a
results of formation of very large secondary grains.

13. IN PROPOSED WORK
 Plastic deformation of material at particular temperature
range influence on micro structure to refining the grain
size and improve the mechanical properties.
 The strength of the material increases with increasing
the plastic strain .
So we would like to study the different strain rate.
 The main objective of strengthening mechanism is to
refine the grain size.
 As the finer grains have better strength or mechanical
properties than the coarser grains.

14. THANK YOU