ExperimentalDetailsMaterialSelectionMatrix material Aluminum 6063 was used as matrixmaterial owing to its excellent mechanical properties coupled with goodformability and its wide applications industrial sector.The Physicalcomposition of the material is given in table 1 Sl.
No Property Value 1 Density 2700 kg/m3 2 Melting Point 600°C 3 Modulus of Elasticity 69.5 GPa 4 Electrical Resistivity 0.035×10-6 ?.m 5 Thermal Conductivity 200 W/m.K 6 Thermal Expansion 23.5 x 10-6 /K Table 1 showsPhysical composition of Al6063 The Chemical composition of the material is given intable 2 Elements Si Fe Cu Mn Mg Al % (max.) 0.2%-0.
6% 0.35% 3 0.10% 4 0.8 0.10% Balance Table 2 shows chemical composition of Al6063 ReinforcementSiliconCarbide was chosen as reinforcement owing its high hardness and lowco-efficient of thermal expansion.
SiC is highly wear resistant and also hasgood mechanical properties, including high temperature strength and thermalshock resistance. The particle size of the reinforcement used are in rangeof 10µm to 20µm.Preparation ofComposites Abatch of 3.5kgs of Aluminum 6063alloy was melted using a 6KW electric furnace as shown in Fig4.1.
The moltenmetal was agitated by use of mechanical stirrer rotating at a speed of 300 rpmto create a fine vortex. Preheated SiCpowders (preheated to 700oC for 2 hrs) were added slowly in to the vortexwhile continuing the stirring process. The stirring duration was 10 min. The composites melt maintained at a temperature of 710oc wasthen poured in to metallic molds as shown in Fig 2.
The stirrer blades made of stainless steeland were coated with ceramic material to minimize the iron pickup by the moltenmetal. The amounts of SiC was variedfrom 0 to 8wt% in steps of 2 wt%.Preparation of SamplesThe samples were prepared forhardness test, tensile test, Compressive tests. The samples were prepared for the above tests to find mechanicalproperties. The photographs of the samples prepared for the above tests aregiven belowFig 3Preheating of mouldFig: 4Pouringof molten material into mould Fig 5 Specimenprepared for Tensile testingFig 6 Specimenfor Compression testFig 7 Specimenfor Hardness testFig 8 Specimenattached in UTM for tensile test Fig 9:Outputresult of tensile test Resultand Discussion Sl.No %SiC by Weight Hardness in BHN Average Hardness in BHN Section 1 Section 2 Section 3 1 0 28.5 28.
5 28.5 28.5 2 2 31 31 32 31.33 3 4 39.5 39 39 39.16 4 6 45 45.5 46 45.5 5 8 58 57.
5 58 57.83 The variation of hardness with increase content ofSiC particles in the matrix Al6063 in as cast condition and with reinforcementvarying from 0-8% SiC is shown in Fig. 10. It is observed that with increase in percentage of Silicon carbide the hardness is increaseedFig10: Brinell hardness number for different Wt % of SiC Fig11: Compression strength for different Wt % of SiC The test results reveal that as wt % of SiC isincreased the compressive strength is also decreased there is a very drastic decrease in compressivestrength for 2% may be due to improper casting or casting defectsFigure 11 shows the test results fordifferent Weight percentage of Silicon carbide added in Aluminum 6063 there isa fair result obtained as silicon carbide is ceramic material and it is brittlein nature the strength has decreased with increase percentage addition toaluminum 6063 alloy Fig 12Load at YieldFigure5.3 shows that the load at which theyielding started for different weight percentage of Silicon carbide and fromthe test results reveals a very fair results, as it is observed from the graphfor 0% of SiC the load at the yield is 5.46, and at 2% the load is increased to7.
3 there is increased in the load carrying capacity of material with increasein silicon carbide as aluminum is ductile in nature and silicon carbide isbrittle in nature so reinforcing the silicon carbide the load taking ability ofmaterial is increased the table below shows the variation of loads at yields L:oad at Yield 0 5.46 2 7.3 4 9.
28 6 9.46 8 8.56 5.2.2Elongationat Yield Fig 13Elongation at yield Figure5.
4 shows that beginning of Elongation as yielding of specimen starts for differentweight percentage of SiC, as it is observed from the graph for 0% of SiC theelongation at yield is 13.6 and at 2% elongation is increased to 16.37, at 4%26.08mm, there after there is sudden decrease in elongation withincrease in SiC, the elongation is property of ductile material as SiC isincreased the elongation is decreased as SiC is ceramic material which is verybrittle in nature. table below shows the variation of elongation. Elongation at Yield 0 13.6 2 16.37 4 26.
08 6 20.35 8 13.94 5.2.3Yield Strength Fig 14 Yield StrengthFigure5.
5shows that the yield strength at which the yielding started for differentweights percentage of SiC and from the test results. Yielding of material isnothing but the point where the material just start changing its shape andsize. As it is observed from graph for 0% of SiC i:e Pure Aluminum 6063 alloythe yield strength is 45.286 and for 2% the yield strength is increased to60.158.
The yield strength of material is increased upto 6% of reinforcement ofSiC there after there is sudden drop in yield strength with is increase in SiC.Due to improper weight fraction of SiC and aluminum alloy 6063, The table belowshows the values of Percentage variation to yield strength values. Yield Stress 0 45.286 2 60.158 4 76.229 6 112 8 70.541 Fig 15 Tensile strengthFigure5.
7shows the variation of tensile strength for different weight percentage of SiC.Tensile strength is the major properties in mechanical properties the material’s tensile property defines aboutmaterial strength in tension. The test is conducted for tensile strength fordifferent weight percentage of SiC asreinforcement in Aluminum 6063 alloy in step of 2% from 0%to 8%, in order toincrease the tensile strength of material.
The test result reveal a very fairresult, as it is observed from the graph for 0% of Sic the tensile strength is82.775, at 2% of SiC the tensile strength increases to 75.815 , at 4% of SiCthe tensile again increases to 86.415 at 6% and further there is increase inthe tensile strength to 90.
319 at 8%. So its is concluded from the graph withincrease in reinforcement of SiC there is increase in Tensile strength. Thetable below shows the values of Weight Percentage variation of SiC to Tensilestrength values.
Tensile Strength 0 82.775 2 75.815 4 86.
415 6 92.288 8 90.319 Percentage Reduction in AreaFig 16 %reduction in areaFigure shows the percentage reduction in area withdifferent weight percentage of SiC and from test results reveals a very fairresults, as it is observed from the graph for 0% of SiC the percentagereduction in area is 5.41 and at 4% of SiC the percentage reduction in area is4.98 further there is decrease in the percentage reduction in area. The area ofreduction at the point where it breaks. With increase in SiC Deformation ofmaterial reduces as the property of material starts changing from ductile tobrittle.
The area calculated is know as Cup and Cone fracture measured wherethe fracture takes place. The tablebelow shows the values of Weight Percentage variation of SiC to Percentagereduction in area % Reduction Area 0 5.41 2 4.98 4 4.
76 6 4 8 3.55 CONCLUSIONS Silicon carbide particle reinforcedaluminium matrix composite 6063 (AMCs) were prepared by stir-casting with differentparticle weight fraction (0%,2%, 4%, 6%, and 8%) the following conclusions canbe drawn:Ø Thecomposites containing 6063Al with 0,2,4,6 and 8wt% of Silicon particulates weresuccessfully synthesized by melt stirring method using three stages mixingcombined with preheating of the reinforcing particles.Ø Hardnessof Al-SiC is much better than the aluminum metal. In case of increased siliconcarbide content, the hardness, and material toughness are enhanced and highestvalue is obtained at 8% SiC content.Ø Homogenousdispersion of SiC particles in the Al matrix shows an increasing trend in the samplesprepared by without applying stirring process, with manual stirringØ Ithas been inferred that the tensile strength of sample 4 is marginally higherthan other samples because of itsaluminum content.
Ø Ithas been noted that the Compressive strength of sample 1 is higher than othersamples.