412
J. Sundaram et al.
Royal Scientific suppliers, India, alumina (40 nm) from M/s US research nanomaterials corporation and titanium diboride (20 nm) from M/s Guangzhou Hongu
Material Technology Company were procured.
Elemental powders of the aluminum AA2014 alloy, TiB 2 and Al 2 O 3 were
measured in 50 g of weight percentage through electronic weighing machine (Make:
SHIMADZU, Model AUY220) with precision of 0.001 g. Measured powders were
mixed in pot mill for 12 h. Powders were allowed to flow in a die of high carbon
high speed steel of the 50 mm of diameter and 12.5 mm height. Die’s inner surface,
punch, and butt outer surface were pasted with mixture of acetone and zinc stearate
punch for removal of samples without damages [20]. Lauric acid is used as lubricator
in the die wall for easy removal and avoiding damages of samples from the die [21].
Green compaction was done in hydraulically operated universal testing machine at
pressure of 350 MPa. In the UTM (Make: Fine Spavy Associates & Engineers Pvt Ltd,
Model TUN 400), when compaction pressure increases gradually, particles movement is stopped; as pressure gradually increases, it is used for powder compaction
which involves process fragmentation and plastic deformation of powders [22].
After removal of billets from the die, green densities were measured using electronic weighing machine. Samples were kept inside chamber of electrical muffle
furnace (Make: Geniune Equipment Manufacturers, Model:MF01) for sintering at
550 °C for 2 h which involves densification and bond formation using furnace atmosphere. Sintered densities were measured after removal of samples from electrical
muffle furnace. Samples were kept inside chamber of vacuum hot press (Make:VB
CERAMICS) for hot pressing at 620 °C with 360 MPa in nitrogen atmosphere for
2 h.
Sintered density was determined by Archimedes’s principle. Porosity of samples
was derived by using the formula [23].
Porosity = (ρth−ρexp)/(ρth−ρair) ∗ 100.
where ρth—theoretical density in g/cm
3 , ρexp—experimental density in g/cm
3 ,
ρair—density of air (0.001225 g/cm
3 ).
Microstructural analysis was carried by Metscope–I supplied by Chennai Metco;
tensile strength of samples was analyzed in Hounsfield Tensometer with ASTM
standard E8. Hardness was measured in Rockwell hardness tester make Navin Engineering, Model RHS 150 of Capacity 150 kgf in B scale. Billets were made into
mirrors like polishing with double disk polishing machine with emery grades sheets
of size 800, 1000 and 1200 and velvet with diamond paste. Billets were etched with
Keller’s reagent (HNO 3 + HCl + HF) for micrographs examination [24]. Samples
were arranged inside the chamber of vacuum hot press for hot pressing at 610 °C
± 10 °C under vacuum condition for 2 h in order to improve existing mechanical
properties.
J. Sundaram et al.
Royal Scientific suppliers, India, alumina (40 nm) from M/s US research nanomaterials corporation and titanium diboride (20 nm) from M/s Guangzhou Hongu
Material Technology Company were procured.
Elemental powders of the aluminum AA2014 alloy, TiB 2 and Al 2 O 3 were
measured in 50 g of weight percentage through electronic weighing machine (Make:
SHIMADZU, Model AUY220) with precision of 0.001 g. Measured powders were
mixed in pot mill for 12 h. Powders were allowed to flow in a die of high carbon
high speed steel of the 50 mm of diameter and 12.5 mm height. Die’s inner surface,
punch, and butt outer surface were pasted with mixture of acetone and zinc stearate
punch for removal of samples without damages [20]. Lauric acid is used as lubricator
in the die wall for easy removal and avoiding damages of samples from the die [21].
Green compaction was done in hydraulically operated universal testing machine at
pressure of 350 MPa. In the UTM (Make: Fine Spavy Associates & Engineers Pvt Ltd,
Model TUN 400), when compaction pressure increases gradually, particles movement is stopped; as pressure gradually increases, it is used for powder compaction
which involves process fragmentation and plastic deformation of powders [22].
After removal of billets from the die, green densities were measured using electronic weighing machine. Samples were kept inside chamber of electrical muffle
furnace (Make: Geniune Equipment Manufacturers, Model:MF01) for sintering at
550 °C for 2 h which involves densification and bond formation using furnace atmosphere. Sintered densities were measured after removal of samples from electrical
muffle furnace. Samples were kept inside chamber of vacuum hot press (Make:VB
CERAMICS) for hot pressing at 620 °C with 360 MPa in nitrogen atmosphere for
2 h.
Sintered density was determined by Archimedes’s principle. Porosity of samples
was derived by using the formula [23].
Porosity = (ρth−ρexp)/(ρth−ρair) ∗ 100.
where ρth—theoretical density in g/cm
3 , ρexp—experimental density in g/cm
3 ,
ρair—density of air (0.001225 g/cm
3 ).
Microstructural analysis was carried by Metscope–I supplied by Chennai Metco;
tensile strength of samples was analyzed in Hounsfield Tensometer with ASTM
standard E8. Hardness was measured in Rockwell hardness tester make Navin Engineering, Model RHS 150 of Capacity 150 kgf in B scale. Billets were made into
mirrors like polishing with double disk polishing machine with emery grades sheets
of size 800, 1000 and 1200 and velvet with diamond paste. Billets were etched with
Keller’s reagent (HNO 3 + HCl + HF) for micrographs examination [24]. Samples
were arranged inside the chamber of vacuum hot press for hot pressing at 610 °C
± 10 °C under vacuum condition for 2 h in order to improve existing mechanical
properties.