CHAPTER 2
LITERATURE REVIEW
2.1 Introduction
In this excellent chapter, those things that have discussed are about the phase that use in the study. It is consists the theory of the research and the journal that discovered from the previous researches. A few of the resources to complete this analysis even get from publications, and also previous studies that make by past student. There are some examples of case studies to maximize the efficiency of aluminum alloys made by many researchers.
Literature review is being accomplished by two methods which are basic principle part and from previous researcher's journals. In theory part, it might cover the definition and the features which all are really concerning the knowledge of aluminum alloys as well as its processes. For the previous researchers part, it will concentrated on contain of use materials, experimental method, the processes requirement and also the impact for all experiment. This analysis will helps out due to making this research. It will be information to complete the research.
2.2 Theory
2.2.1 Aluminum alloys
The practicality of it is use within the electric power industry in light of good electrical conduction, agreeable atmospheric crumbling resistance, and in addition low density of aluminum and in addition for supplant of coal- graphite on account of the continuously break down throughout stuns due to low invulnerability to brittle fracture. a not large amount (the same as 15%) of softer part can abatement bond that will lessen the inconsistency of friction surfaces and influence insignificantly the electrical conduction. [6]
Aluminum and furthermore its alloy own astounding properties for instance low occurrence, exceptional versatility and likewise malleability, and moreover good corrosion resistance. They have been utilizing as a part of aeromechanics, astronautics, and also auto and additionally high speed train areas. They likewise have constraint in ample obligation surrounding because of poor influence resistance and poor firmness. It have been demonstrated that particles secured aluminum matrix composites might be enhance with the great deal the force and augmentation hardness of aluminum and its alloy. At the same time, it can decrease the versatility and ductility. [2]
2.2.2 Mechanical Properties
Deformation processed metal composites (DMMCs) are materials where the arranged filamentary microstructure is made through severe plastic distortion. The segments are usually considered as "in situ composites" when that filamentary microstructure is shaped within the specimen. DMMCs are processed by billets are ready with powder metallurgy or casting methods, then after that shaped by axisymmetric deformation for instance expulsion, wire drawing or possibly rolling. [7]
Aluminum is barely one of the vital adaptable of the normal foundry metals in addition to the proportion of cast to wrought aluminum alloys items is expanding primarily with the more extensive results of castings being used for auto fields. A mixture of cast aluminum alloys is introduced for commercial use. Aluminum has a low modulus of flexibility and separated from indium, lead has the least modulus of versatility of every bit of the delicate stages alloying with aluminum. [8]
Al- Sn-based alloys are know in sliding bearing within the aviation and auto provisions on account of their heightened wear in resistance, comparability and likewise conformability. Resulting from the fact that Al- Sn combinations incorporate delicate Sn, the fed has great anti-friction characteristics. The similarity of Al- Sn combination is near the tin- based handled metals; in addition to the weakness constancy of transformed metals is height. [9]
2.2.3 Tensile Test
The tensile property measurements were carried out using ASTM E 8m. the gauge length was 45mm and all results are averages of at least 3 measurement. The test specimens were smooth and cylindrical in the gauge section with 9.0 mm in diameter and 100 mm in length as shown in Fig. 1. The test specimens were mechanically polished by 600 grit silicon carbide paperin order to minimize the effects of surface irregularities and finish the entire gauge section of the test specimens. 3 samples were tested to get an average value. The crosshead speed of testing for all samples is 2mm/min. Initially the gauge region elongates homogenously until it reaches a point at which one cross-sectional slice yields independently of the rest of the specimen. The onset of heterogeneous elongation corresponds to the yield section. [10]
Figure 2.1 Tensile specimens as per ASTM E 8m standard
Figure2.2 Effect of reinforcement content on modulus of elasticity of composites
2.2.4 Impact Test
To study more concerning the complex nature of break in materials impact testing conditions were created. The conditions that were judged the most in respect to the potential for fracture are:
i. deformation at low temperatures.
ii. a high strain rate (rate of deformation)
iii. a triaxial stress state
To investigate the impact energy, two tests are called the Izod and Charpy test are used. This test is very important because it can give information to model the behavior of the real structure so that the test result can be used to give an information performance under other environment. The specimen is in the bar square shape cross section with the V notch and know as the Charpy V-notch (CVN). A weight 17 pendulum hammer as the load impact will release from a position h. the pendulum with a knife edge will strikes the specimen at the notch. The pendulum continues swing and rising to a maximum height h'. The test is calculated from the different in initial and final heights of the pendulum swing. The impact energy from the Charpy test is identified to the area under total stress-strain curve. Way that the specimens are attaching in the apparatus machine is the different between Charpy and the Izod techniques. One can expect that materials that have large impact fracture energies will have large values of strength and ductility. Note that the specimen size, temperature, and notch configuration are sensitive to test to the impact data. [11]
Figure 2.1 Charpy specimens as per ASTM E standard
2.2.4 Application
2.2.4.1 Electrical Conductors
Conductors such as 1000 or 6000 series alloys are practical technical alternatives to copper for all electrical conductors, such as domestic wiring. The conductor on weight grounds are very large proportionality of overhead, high volume of voltage, energy marks utilize aluminum rather than copper as. Because of relatively poor strength of these level requires that they been reinforced by including a galvanized or aluminum coated with high tensile steel wire in each of strand. Aluminum alloys feature a conductivity averaging 62% of the International Annealed Copper mineral Standard (IACS) however, it could maybe carry greater than double because lot electricity as any equivalent weight of copper due to its density.
2.2.4.2 Transport
Aluminum and its alloys have been the important material of construction for the aircraft industry throughout nearly all of its history. 70% of commercial aircraft airframes today are made from aluminum alloys even titanium and composites are growing in use, and without aluminum civil aviation would not be economically viable. It's because of acceptable cost; low component mass, appropriate mechanical properties, structural integrity and also ease of fabrication are also appealing in other regions of transportation. Today, there are really very many types of it is utilize in commercial cars, train vehicles passenger and freight, nautical hulls and superstructures and military vehicles. Volume auto production now incorporates aluminum as motor castings, wheels, radiators and in an every expanding degree as body parts. For general preparation, the 5000 and 6000 sequence composites furnish sufficient ability consolidated with great corrosion resistance, high toughness and simplicity of welding. Amount car manufacturing now contains aluminum since engine castings, rims, radiators and additionally increasingly as body components. For average production, the 5000 and also 6000 series alloys offer adequate power matched with good deterioration resistance, high toughness and also ease of welding. In aircraft the powerful 2000, 7000 and also 8000 series alloys are really preferred, and also in martial automobiles the wieldable 7000 show alloys can provide ballistic qualities to suit steel armor.
2.2.4.3 Packaging
The use of the 1000 series alloys because foil for food wrapping and also for containers utilizes their good corrosion resistance and additionally barrier properties against moisture, UV light and also smells. If required, foil can be commonly formed, attractively designed and can be usefully coupled with paper and plastic. Aluminum cans for some food products, particularly fish, which also use the straight forward opening amenities of aluminum, have been used in around the world over sixty years. From a technical aim of see indeed there is not a main reason the reasons why even more use cannot be manufactured aluminum as a can material, to date prices appear to feel the restraining aspect.
2.2.4.4 Building and Architecture
Aluminum is usually used in buildings for a wide of applications including roofing for factories which incorporate foil vapor divider, table and chair, canopies, door and fronts for shop and building, architectures hardware and fitting and replacement windows. The durability of aluminum is of paramount importance in building application. Today, even more recently the oil and gas industry has employed aluminum highly in offshore structures. The 1000, 3000, 5000 and 6000 wrought series alloys could perform, without having decreased their strength, with no protection even in industrial and marine conditions. However they might sustain some deterioration in their look and protection by painting or anodizing can be advisable.
2.2.4.5 High Pressure Gas Cylinders
Pressurized fuel cylinders with the capacities to as much as 50 liter capacity for storage and transportation of CO2, air, oxygen and additionally special gases. Light body weight, good corrosion resistance, compatibility with the product to be included and mechanized toughness is really combining in the 6000 series alloys.
.
2.2.4.6 Machined Components
2000 and 6000 series alloys can be machined due to high tolerance components. These alloys are able to machine that approaches that of the free machining brasses because they have addition of leaf and bismuth[12]
2.3 Past Research
V. V. Shyrokov., (2010) have studied tribological properties and structural features of pseudo alloys of the aluminum-tin system. In the present work, he investigates the influence of tin on the structure and wears resistance of alloys of the aluminum-tin system in friction with copper. If the tin content is 2 mass %, equilibrium precipitates of spherical shape with a diameter up to 1.5 μm are formed; if it is 10 or 15 mass %, precipitates lengthen to 30-40 μm, and liquation appear in the ingots of alloys. He recorded an increase in the tin (more plastic and low-melting phase) content on the surface, which a decrease in wear. Here, the surface profile smoothens (its height parameters decrease by an order of magnitude). Its influence becomes ambiguous because the transport of copper takes place. When increase in the friction speed to 5.4 m/sec and at low tin concentration (2 mass %). [6]
Hyun Kyu Lim., (2007) have studied the Effect of grain size on the tensile deformation of wrought Mg-MM-Al-Zn-Sn alloy. Due to the demand as structural material with high specific strength, light-weight alloys for structural applications, magnesium alloys are receiving attention. Micro structural parameters such as grain size, texture, second solidification phase, precipitation and etc are affected the mechanical properties of magnesium alloys. EAZT211 rolled sheet specimens with the smallest grain size (~10 μm) exhibit the highest yield strengths (~190 MPa). Finer crystallized grains due to the activation of non-basal slip system during deformation at room temperature were observed by an investigated the yield phenomenon. [13]
Hsueh-Chuan Hsua., (2008) have investigated Mechanical properties and deformation behavior of as-cast Ti-Sn alloys. Dental cast machine is using to prepared to determine the mechanical properties of as-cast Ti-Sn alloys with Sn content ranging from 1 to 30 wt.%. All the Ti-Sn alloys shows higher bending moduli, bending strengths and elastic recovery angles than those of c.p. Ti and the alloys showed brittle characteristic when the Sn content was 20 wt.% or greater. [14]
Alan A. Luo., (2011) investigated solidification microstructure and mechanical properties of cast magnesium-aluminum-tin alloys. The strength and creep resistance of the alloys were improved by addition of Sn to Mg-Al alloys. For microstructure and mechanical properties, no systematic investigation has been done of the Mg-Al-Sn system. Based on these calculations and experiments, a promising new Mg-7Al-5Sn alloy with significantly improved strength and ductility compared with the commercial AZ91 alloy has been identified. Based on calculation, the experiments have also explained the high elongation of a leaner Mg-7Al-2Sn alloy based on the amount of secondary phase formed in the microstructure. With increasing Al and Sn content, the grain size of the as-cast Mg-Al-Sn alloys was shown to decrease because of an increase in the amount of eutectic phases formed, which restricted the growth of a-Mg grains during solidify process. [15]
Q. Xiang, R.Z.Wu., (2008) investigated Influence of Sn on microstructure and mechanical properties of Mg-5Li-3Al-2Zn alloys and the grain size of alloy is refined by addition of Sn in Mg-5Li-3Al-2Zn alloy. The size of alloy is the finest when the content of Sn is 1.0%. Formation of Mg2Sn strengthening phase and refining effect are improved the strength of the alloys by addition of Sn. The strength is the highest (306.95MPa) when the content of Sn is 1.0%. [16]
F. Abd El-Salama., (2009) hve studied effect of Sn content on the structural and mechanical properties of Al-Si alloy. Sn addition improved the mechanical properties of the samples. Sn is a suitable component in a bearing because of its excellent anti-welding characteristics with iron, low modulus and low strength. The increased temperature caused softening in the studied Al-Si-Sn alloys, increased hardening; the magnitude of variation depends mainly on the composition of each alloy causes by the increasing Sn content. The affectability of the mechanical parameters to a certain component should not be the same for a given structure. [4]
Hiroaki Matsumotoa., (2010) have studied mechanical behaviors of Ti-V-(Al, Sn) alloys with martensite microstructure. As-quenched Ti-V-Sn alloys, good cold-rolling ability with a reducing of more than 80% that is independent of phase constituents is seen. Tensile-deformed at a strain of 5% in martensite Ti-V-Al-Sn alloy with compositions in −(+), in alloy that by having a low Al content, a homogenous deformation substructure with directly dislocations is observed. In alloy with a low Al content a homogenous deformation substructure is seen, In martensite Ti-Al-6%V-2%Sn alloy with a composition of near-−(+) that was tensile-deformed at a strain rate of 5%. The change in deformation substructure by increasing the Al content will cause the low ductility of the material. Besides that, plastic material deformation is found to be preceded via to the activation of the basal a slip. [17]
O. Hernández., (2007) have studied microstructural and mechanical behavior of highly deformed Al-Sn alloys. Sn phase developed a lamellar morphology and geometrical aspects during the cold rolling,as its separation and thickness were correlated with the composite's tensile strength. In order to measure the micro strains inside the matrix, a study of the peak broadening was create by using X-ray diffraction and the related them with the macroscopic strength. The thickness and the space between the second phase decrease in a non linear way with a different profile in both cases as the Al-Sn composite is deformed. [7]
Palash Poddar., (2012) investigated microstructure and mechanical properties of conventional cast and rheo cast Mg-Sn based alloys. The matrix grain size became finer with the addition of Al-Sc master alloy inMg-8%Sn alloy. Mg2Sn inter metallic in Mg-Sn alloys leaded to completed is solution heat treatment at 520oC for48-72h. The tensile properties of conventional cast alloys were significantly lower than rheo cast alloys. [18]
G.C. Yuan., (2000) investigated on crystallization and microstructure for new series of Al-Sn-Si alloys. They possess good anti-friction characteristics because Al-Sn alloys contain soft Sn. due to hard Si contained, Al- Si alloys show excellent wearing-resisting characteristics. It has been shown that they do not fit with the needs of high velocity and load of engines although the two categories of alloys meet many of the service requirements, such as high strength-to-weight ratio, excellent corrosion resistance, good bearings qualities and lower expansion characteristics. Al-Sn alloys lack enough abilities of supporting load and resistance to fatigue by improving of press-increasing techniques for engine. Low resistance to seizure makes Al-Si alloys vulnerable under poor lubricating conditions, especially during starting and warming-up of engines. To overcome these problems so that their ability of supporting load and resistance to fatigue is improved, there has been an increasing trend of adding Si into Al-Sn alloys. [9]
Jing Wang., (2011) investigated the mechanical properties and microstructure of as-cast Mg-Al-Sn-Y-Nd alloy. Because of good mechanical properties at elevated temperature Mg-Sn-based alloys have attracted strong interest. He investigated that Mg-Sn-based alloys are suitable for plastic deformation process. With good ductility and relatively low yield asymmetry Mg-Sn-Al-based alloys are known to be good prospect to high performance wrought alloys development. Mg-4Al-2Sn-0.5Y-0.4Nd alloy shows the best mechanical properties. Tensile strength is increased from 220 to 225 MPa and elongation from 15.6% to 23.2%. [19]
X. Tenga., (2009) have studied probability characterization of tensile strength of an aluminum casting. The zone decrease of the break surface, the discriminating elongation of the check area, and the joined together experimental-numerical analysis are dead set to investigate the tensile break. Since large pores induce localized plastic deformation and subsequent crack formation, it was known that using the critical elongation significantly underestimated the fracture strains. A linear correlation between ultimate tensile strength and the projected area of pores was established. The value of Pearson's correlation coefficient is use to verified the linear function. The calibration shows the maximum value of the ultimate tensile strength in the case that no defects occur in the sample. [20]
K. Xu,. (2000) have studied a deformation processed al-20%sn in-situ composite. The billet is produced by using a powder metallurgy process. Although Al-Sn widely used as bearing, the amounts of deformation tangled up in this research are substantially higher than those employed in bearing manufacture. The ultimate tensile strength of Al-20%Sn composite increasing exponentially with the deformation of true strain. The relation between ultimate tensile strength and deformation true strain is UTS=74.3 [21]
Dr.Eman J. Abed,. (2012) investigated the study of solidification and mechanical properties of al-sn casting alloys. This combination is good for a strength and surface properties. This study is to investigated the mechanical behavior of Al-Sn alloys and tin content (20%, 30%, 40%Sn). With the increasing of the Sn, result shows that the hardness and ultimate tensile stress decrease. Increasing of bonding between Al matrix and Sn phase also decrease because of increasing of the tin content. [22]
Wang Qing., (2010) investigated study on microstructure and mechanical properties of as-cast Mg-Sn-Nd alloys. The highest ultimate tensile strength of 140 MPa and also percentage elongation after fracture of 9.7%, were attained by having a structure of Mg-8.23 wt.% Sn-2 wt.% Nd. The ultimate tensile strength and additionally elongation increased very first and additionally then decreased with the increase of Sn. [23]
Dr.Eman J. Abed,. (2011) have studied the influence of different casting method on solidification time and mechanical properties of AL- Sn castings. This excellent paper presents influence of different casting strategy on solidification time and mechanical characteristics of Al-(20%-40%) Sn alloys against the molding circumstances and additionally tin content. The most usually process in casting are permanent mould casting, hot chamber pressure die casting, CO2 casting and cold chamber. The solidification time of Aluminum-%Sn alloys in sand casting is obviously greater when compared to the solidification time of Aluminum-%Sn alloys in die casting. Compressive strength and elastic modulus is decrease because of the increase of tin content from 20% to 40%. [8]
Wenlong Xiao., (2010) investigated Effects of Sn content on the microstructure and mechanical properties of Mg-7Zn-5Al based alloys. The microstructures and tensile properties of the as-cast and heat treated Mg-7Zn-5Al based alloys with 1-6 wt.% Sn addition were investigated. The yield strength of the as-cast alloys increases with increasing Sn content and more Sn addition lower the tensile strength and ductility due to the formations of large Mg2Sn particles and continuous phase along the grain boundaries. The aged Mg-7Zn-5Al-2Sn alloy exhibits optimal tensile properties and additionally heat resistance, just where the ultimate tensile strength, yield strength and additionally elongation at just 150 â-¦C are 187 MPa, 148MPa and additionally 3.3%, respectively. [24]
2.4 Summary of Past Research
Sn addition improved the mechanical properties of the samples. Sn is a suitable component in a bearing because of its excellent anti-welding characteristics with iron, low modulus and low strength. The increased temperature caused softening in the studied Al-Si-Sn alloys, increased hardening; the magnitude of variation depends mainly on the composition of each alloy causes by the increasing Sn content. It can improved the strength of the alloys by addition of Sn. Sn addition also improved the mechanical properties of the speciment. [4][16]
All the Ti-Sn alloys shows higher bending moduli, bending strengths and elastic recovery angles than those of c.p. Ti and the alloys showed brittle characteristic when the Sn content was 20 wt.% or greater. [14]
It shows that by increasing Al and Sn content, the grain size of the as-cast Mg-Al-Sn alloys was shown to decrease because of an increase in the amount of eutectic phases formed. The ductility decreased when the yield strength of the as-cast Mg-Al-Sn alloys increased with alloying content because of an increase in the amount of eutectic phases formed, which reduced the grain size. [15]
With good ductility and relatively low yield asymmetry Mg-Sn-Al-based alloys are known to be good prospect to high performance wrought alloys development. Tensile strength is increased from 220 to 225 MPa and elongation from 15.6% to 23.2%. [19]
With the increasing of the Sn, result shows that the hardness and ultimate tensile stress decrease. Increasing of bonding between Al matrix and Sn phase also because of increasing of the tin content. [22]
Investigated study on microstructure and mechanical properties of as-cast Mg-Sn-Nd alloys. The ultimate tensile strength and additionally elongation increased very first and additionally then decreased with the increase of Sn. [23]
The solidification time of Aluminum-%Sn alloys in sand casting is obviously greater when compared to the solidification time of Aluminum-%Sn alloys in die casting. Compressive strength and elastic modulus is decrease because of the increase of tin content from 20% to 40%. [8]
The yield strength of the as-cast alloys increases with increasing Sn content, while the more Sn addition will reduces the ultimate tensile strength and ductility due to the formations of large Mg2Sn particles and continuous phase along the grain boundaries. The aged Mg-7Zn-5Al-2Sn alloy exhibits optimal tensile properties and additionally heat resistance, just where the ultimate tensile strength, yield strength and additionally elongation at just 150 â-¦C are 187 MPa, 148MPa and additionally 3.3%, respectively. [24]
