OCTOBER 19-20, 2012 - YMCA University of Science & Technology

Proceedings of the National Conference on
Trends and Advances in Mechanical Engineering,
YMCA University of Science & Technology, Faridabad, Haryana, Oct 19-20, 2012
FVS 8009 alloy develop by Allied Signal Company was produced by rapid solidification processing (RSP) route
which contents Al-8Fe-1.5Si-1.7V. But RSP routes have some limitations, as the product size is limited and
product produced is not of uniform in size, so difference in microstructure. Recently Al-8.3Fe-0.8V-0.9Si alloy
has produced by melting in casting route, which has ten-armed star shaped structure [11]. In this alloy, both the
strength and ductility are less due to fact that the sharp corner of the star shaped clusters acts as a stress raiser.
Therefore, lower Fe (2%), V (1%) and Si (1%) were used for this investigation. The present paper reports the
effect of treatment on the properties and modification on microstructure of Al- 2 Fe-1V-1Si alloys.
2. EXPERIMENTAL PROCEDURE
For the preparation of Al-Fe-V-Si alloys, electrolytic grade Al (99.95% purity), Al-21% Fe, Fe-V (V content
50%) and pure silicon (99.99% purity) were used (all compositions are in wt.%). Master alloys were crushed into
small pieces for easy melting. The compositions of different alloys investigated in the present study are shown in
table 1. The experimental alloys were prepared in an electric heating furnace in a clay bonded graphite crucible
under the cover of Na-free flux. Na-free flux is used because Na addition increases the pin holing tendency and
reduces fluidity.
First, crucible was preheated to about 600 0 C. At around 600 0 C, weighted quantity of master alloys (Al-21%Fe,
Fe-50%V), and 99.9% pure Al and 99.9% pure silicon metallic were charged. Just after melting, the molten alloy
was covered with a Na-free flux (2% of melt). After melting, sufficient time was given for complete
homogenization of the melt. The melt was frequently agitated with a graphite rod for complete mixing. The
cover flux, in the form of scaling and dross etc. were skimmed off before the degassing treatment. The melt was
then degassed with hexachloroethane. Degasser was wrapped in Al foil and plunged into the melt. After
degassing, the melt was cast in different moulds. The object was to vary the cooling rates.
After complete homogenization at desired temperature, the melt was poured in different mould to prepare
different samples. The degassed unmodified as well as modified melts were poured into permanent moulds in the
0
form of rods and plates (cooling rate 30 K/s). The pouring temperature was maintained approximately at 880 C.
The fluidity of the melt at this temperature was sufficient for casting test pieces. Metallographic samples were
cut from all the heats of test pieces and polished using belt polishing, emery paper from coarser ranges to finer
one. After that, cloth polishing was done using fine alumina powder. Finally, the samples were polished with
silvo solution. Silvo polish solution is trade name which contents iso-propyl alchohol, ammonium hydroxide and
silica powder crystalline which is used for cleaning and suspending the turnish on surfaces and also protect from
oxidation
The samples were etched with a modified Keller’s reagent (2ml HF and 3ml HCl in 175ml water) for micro
structural studies in an optical microscope. The microstructures of the samples were taken with the help of an
image analyzer (LECO) in order to distinguish the shape and size of the primary and interdendritic precipitates.
The specimens were also examined in a Scanning Electron Microscope (SEM) fitted with an Energy Dispersive
X-ray analysis (EDX) system.
The hardness from all the samples was measured in Vicker’s hardness testing machine. A load of 5Kg was
applied for testing hardness. Average of four measurements of each as cast samples was taken. The specimens
were tested in a Hounsfield Tensometer (tensile testing machine) at room temperature at a strain rate of
3mm/min. The Ultimate tensile strength (UTS) and percentage (%) elongation were measured.
Table 1 Composition of the alloys prepared
Alloy Designation Chemical Composition (wt %)
Fe V Si Al
1. H2 2 1 1 Balance,
Unmodified
2. H2M 2 1 1 Balance, Modified
with 1% Ni-20Mg.
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