Abstract: In this investigation, a hypoeutectic AlSi11Cu alloy was printed. This alloy was obtained in powder form with an average particle size of 40 µm. Bars 20 mm in diameter and 100 mm in length were printed with the building direction parallel to the bars' longitudinal direction. The microstructural characterization demonstrated an Al matrix surrounded by a Si network forming a coral-like pattern. The microstructure of the alloy showed a heterogeneous behavior with a mixture of columnar and equiaxed grains. Likewise, the texture indicated that the columnar grains were preferentially oriented towards the building direction, while the equiaxed followed a texture dominated by the cube component. On the other hand, the as-printed material strength showed higher values than those obtained in the same alloy using conventional processes such as casting. In addition, strength and ductility differences were found in the printed material, depending on the measurement direction. The highest values were obtained in the radial direction (565 MPa maximum strength and 4.8% elongation to failure). The lowest values corresponded to the transverse direction (508 MPa maximum strength and 3.2 elongation to failure), which corroborate the material anisotropy.
Abstract: The present study is aimed at investigating microhardness and density of aluminium alloy chips when subjected to various settings of preheating temperature and preheating time. Three values of preheating temperature were taken as 450 °C, 500 °C, and 550 °C. On the other hand, three values of preheating time were chosen (1, 2, 3) hours. The influences of the process parameters (preheating temperature and time) were analyzed using Design of Experiments (DOE) approach whereby full factorial design with center point analysis was adopted. The total runs were 11 and they comprise of two factors of full factorial design with 3 center points. The responses were microhardness and density. The results showed that the density and microhardness increased with decreasing the preheating temperature. The results also found that the preheating temperature is more important to be controlled rather than the preheating time in microhardness analysis while both the preheating temperature and preheating time are important in density analysis. It can be concluded that setting temperature at 450 °C for 1 hour resulted in the optimum responses.
Abstract: In the paper the results of welding of car’s air-conditioning elements are presented. These systems based on, mainly, the environmental unfriendly refrigerants. Thus, the producers of cars will have to stop using traditional refrigerant and to change it to carbon dioxide (R744). This refrigerant is environmental friendly. However, it should be noted that the air condition system working with R744 refrigerant operates at high temperature (up to 150 °C) and high pressure (up to 130 bar). These two parameters are much higher than for other refrigerants. Thus new materials, design as well as joining technologies are strongly needed for these systems. AISI 304 and 316L steels as well as aluminium alloys 5xxx are ranked among the prospective materials. As a joining process laser welding, plasma welding, electron beam welding as well as high rotary friction welding can be applied. In the study, the metallographic examination based on light microscopy as well as SEM was applied to estimate the quality of welded joints. The analysis of welding was supported by numerical modelling based on Sysweld software. The results indicated that using laser, plasma and electron beam welding, it is possible to obtain proper quality of welds in stainless steel. Moreover, high rotary friction welding allows to guarantee the metallic continuity in the aluminium welded area. The metallographic examination revealed that the grain growth in the heat affected zone (HAZ) in laser and electron beam welded joints were not observed. It is due to low heat input and short welding time. The grain growth and subgrains can be observed at room temperature when the solidification mode is austenitic. This caused low microstructural changes during solidification. The columnar grain structure was found in the weld metal. Meanwhile, the equiaxed grains were detected in the interface. The numerical modelling of laser welding process allowed to estimate the temperature profile in the welded joint as well as predicts the dimensions of welds. The agreement between FEM analysis and experimental data was achieved.
Abstract: The present research is a paper on the characterization of aluminum alloy-6063 hybrid metal matrix composites using three different reinforcement materials (SiC, red mud, and fly ash) through stir casting method. The red mud was used in solid form, and particle size range varies between 103-150 µm. During this investigation, fly ash is received from Guru Nanak Dev Thermal Plant (GNDTP), Bathinda. The study has been done by using Taguchi’s L9 orthogonal array by taking fraction wt.% (SiC 5%, 7.5%, and 10% and Red Mud and Fly Ash 2%, 4%, and 6%) as input parameters with their respective levels. The study of the mechanical properties (tensile strength, impact strength, and microhardness) has been done by using Analysis of Variance (ANOVA) with the help of MINITAB 17 software. It is revealed that silicon carbide is the most significant parameter followed by red mud and fly ash affecting the mechanical properties, respectively. The fractured surface morphology of the composites using Field Emission Scanning Electron Microscope (FESEM) shows that there is a good mixing of reinforcement particles in the matrix. Energy-dispersive X-ray spectroscopy (EDS) was performed to know the presence of the phases of the reinforced material.
Abstract: Friction stir welding is the new-fangled and cutting-edge technique in welding applications; it is widely used in the fields of transportation, aerospace, defense, etc. For thriving significant welding joints and properties of friction stir welded components, it is essential to carry out this advanced process in a prescribed systematic procedure. At this moment, Underwater Friction Stir Welding (UFSW) Process is the field of interest to do research work. In the continuous assessment, the study of UFSW process is to comprehend problems occurred in the past and the structure through which the mechanical properties of the welded joints can be value-added and contributes to conclude results an acceptable and resourceful joint. A meticulous criticism is given on how to modify the experimental setup from NFSW to UFSW. It can discern the influence of tool materials, feeds, spindle angle, load, rotational speeds and mechanical properties. By expending the DEFORM-3D simulation software, the achieved outcomes are validated.
Abstract: Partially lubricated sliding wear behaviour of a zinc-based alloy reinforced with 10wt% SiC particles has been studied as a function of applied load and solid lubricant particle size and has been compared with that of matrix alloy and conventionally used grey cast iron. The wear tests were conducted at the sliding velocities of 2.1m/sec in various partial lubricated conditions using pin on disc machine as per ASTM G-99-05. Base oil (SAE 20W-40) or mixture of the base oil with 5wt% graphite of particle sizes (7-10 µm) and (100 µm) were used for creating lubricated conditions. The matrix alloy revealed primary dendrites of a and eutectoid a + h and Î phases in the Inter dendritic regions. Similar microstructure has been depicted by the composite with an additional presence of the dispersoid SiC particles. In the case of cast iron, flakes of graphite were observed in the matrix; the latter comprised of (majority of) pearlite and (limited quantity of) ferrite. Results show a large improvement in wear resistance of the zinc-based alloy after reinforcement with SiC particles. The cast iron shows intermediate response between the matrix alloy and composite. The solid lubrication improved the wear resistance and friction behaviour of both the reinforced and base alloy. Moreover, minimum wear rate is obtained in oil+ 5wt % graphite (7-10 µm) lubricated environment for the matrix alloy and composite while for cast iron addition of solid lubricant increases the wear rate and minimum wear rate is obtained in case of oil lubricated environment. The cast iron experienced higher frictional heating than the matrix alloy and composite in all the cases especially at higher load condition. As far as friction coefficient is concerned, a mixed trend of behaviour was noted. The wear rate and frictional heating increased with load while friction coefficient was affected in an opposite manner. Test duration influenced the frictional heating and friction coefficient of the samples in a mixed manner.
Abstract: A Friction stir welding tool is a critical component to
the success of the process. The tool typically consists of a rotating
round shoulder and a threaded cylindrical pin that heats the work
piece, mostly by friction, and moves the softened alloy around it to
form the joint. In this research work, an attempt has been made to
investigate the relationship between FSW variables mainly tool
profile, rotating speed, welding speed and the mechanical properties
(tensile strength, yield strength, percentage elongation, and micro
hardness) of friction stir welded aluminum alloy 5083 joints. From
the experimental details, it can be assessed that the joint produced by
using Triflute profile tool has contribute superior mechanical and
structural properties as compared to Tapered unthreaded & Threaded
tool for 1000rpm.
Abstract: In this work, repaired crack in 6061- T6 aluminum
plate with composite patches presented, firstly we determine the
displacement, strain and stress, also the first six mode shape of the
plate, secondly we took the same model adding central crack
initiation, which is located in the center of the plate, its seize vary
from 20 mm to 60 mm and we compare the first results with second.
Thirdly we repair various cracks with composite patch (carbon/
epoxy) and for (2 layers, 4 layers). Finally the comparison of stress,
strain, displacement and six first natural frequencies between un-cracked
specimen, crack propagation and composite patch repair.
Abstract: The secondary alloy A226 is used for many
automotive casting produced by mould casting and high pressure die
casting. This alloy has excellent castability, good mechanical
properties and cost-effectiveness. Production of primary aluminium
alloys belong to heavy source fouling of life environs. The European
Union calls for the emission reduction and reduction in energy
consumption therefore increase production of recycled (secondary)
aluminium cast alloys. The contribution is deal with influence of
recycling on the quality of the casting made from A226 in automotive
industry. The properties of the casting made from secondary
aluminium alloys were compared with the required properties of
primary aluminium alloys. The effect of recycling on microstructure
was observed using combination different analytical techniques (light
microscopy upon black-white etching, scanning electron microscopy
- SEM upon deep etching and energy dispersive X-ray analysis -
EDX). These techniques were used for the identification of the
various structure parameters, which was used to compare secondary
alloy microstructure with primary alloy microstructure.
Abstract: To achieve reliable welds with minimum distortion for
the fabrication of components in aerospace industry laser beam
welding is attempted. Laser welding can provide a significant benefit
for the welding of Titanium and Aluminium thin sheet alloys of its
precision and rapid processing capability. For laser welding, pulse
shape, energy, duration, repetition rate and peak power are the most
important parameters that influence directly the quality of welds. In
this experimental work for joining 1mm thick TI6AL4V and AA2024
alloy and JK600 Nd:YAG pulsed laser units used. The distortions at
different welding power and speed of titanium and aluminium thin
sheet alloys are investigated. Test results reveal that increase in
welding speed increases distortion in weldment
Abstract: Aluminium and its alloys have excellent corrosion
resistant properties, ease of fabrication and high specific strength to
weight ratio. In this investigation an attempt has been made to study
the effect of different post weld heat treatment methods on the
mechanical and metallurgical properties of TIG welded joints of the
commercial aluminium alloy. Three different methods of post weld
heat treatments are solution heat treatment, artificial ageing and
combination of solution heat treatment and artificial aging are given
to TIG welded aluminium joints. Mechanical and metallurgical
properties of As welded joints of the aluminium alloys and post weld
heat treated joints of the aluminium alloys were examined.
Abstract: Laser beam welding has wide acceptability due to least welding distortion, low labour costs and convenient operation. However, laser welding for dissimilar titanium and aluminium alloys is a new area which is having wider applications in aerospace, aircraft, automotive, electronics and other industries. The present study is concerned with welding parameters namely laser power, welding speed, focusing distance and type of shielding gas and thereby evaluate welding performance of titanium and aluminium alloy thin sheets. This paper reviews the basic concepts associated with different parameters of Ti/Al sheet joint using Laser beam welding.
Abstract: This paper present a mechanical characteristics on fatigue crack propagation in Aluminium Plate based on strain and stress distribution using the abaqus software. The changes in shear strain and stress distribution during the fatigue cycle with crack growth is identified. In progressive crack in the strain distribution and the stress is increase in the critical zone. Numerical Modal analysis of the model developed, prove that the Eigen frequencies of aluminium plate were decreased after cracking, and this reduce is nonlinear. These results can provide a reference for analysts and designers of aluminium alloys in aeronautical systems.
Therefore, the modal analysis is an important factor for monitoring the aeronautic structures.
Abstract: Tungsten Inert Gas (TIG) welding is a high quality welding process used to weld the thin metals and their alloy. 5083 Aluminium alloys play an important role in engineering and metallurgy field because of excellent corrosion properties, ease of fabrication and high specific strength coupled with best combination of toughness and formability.
TIG welding technique is one of the precise and fastest processes used in aerospace, ship and marine industries. TIG welding process is used to analyze the data and evaluate the influence of input parameters on tensile strength of 5083 Al-alloy specimens with dimensions of 100mm long x 15mm wide x 5mm thick. Welding current (I), gas flow rate (G) and welding speed (S) are the input parameters which effect tensile strength of 5083 Al-alloy welded joints. As welding speed increased, tensile strength increases first till optimum value and after that both decreases by increasing welding speed further. Results of the study show that maximum tensile strength of 129 MPa of weld joint are obtained at welding current of 240 Amps, gas flow rate of 7 Lt/min and welding speed of 98 mm/min. These values are the optimum values of input parameters which help to produce efficient weld joint that have good mechanical properties as a tensile strength.
Abstract: Friction Stir Welding is a solid state welding technique which can be used to produce sound welds between similar and dissimilar materials. Dissimilar welds which include welds between the different series of aluminium alloys, aluminium to magnesium, steel and titanium has been successfully produced by many researchers. This review covers the work conducted in the above mentioned materials and further concludes by showing the need to fully understand the FSW process in order to expand the latter industrially.
Abstract: Through a proper analysis of residual strain and stress
distributions obtained at the surface of high speed milled specimens
of AA 6082–T6 aluminium alloy, the performance of an improved
indentation method is evaluated. This method integrates a special
device of indentation to a universal measuring machine. The
mentioned device allows introducing elongated indents allowing to
diminish the absolute error of measurement. It must be noted that the
present method offers the great advantage of avoiding both the
specific equipment and highly qualified personnel, and their inherent
high costs. In this work, the cutting tool geometry and high speed
parameters are selected to introduce reduced plastic damage.
Through the variation of the depth of cut, the stability of the shapes
adopted by the residual strain and stress distributions is evaluated.
The results show that the strain and stress distributions remain
unchanged, compressive and small. Moreover, these distributions
reveal a similar asymmetry when the gradients corresponding to
conventional and climb cutting zones are compared.
Abstract: The present article deals with a composite casting process that allows to produce bilayer AlSn6-Al strips based on the technique of horizontal continuous casting. In the first part experimental investigations on the production of a single layer AlSn6 strip are described. Afterwards essential results of basic compound casting trials using simple test specimen are presented to define the thermal conditions required for a metallurgical compound between the alloy AlSn6 and pure aluminium. Subsequently, numerical analyses are described. A finite element model was used to examine a continuous composite casting process. As a result of the simulations the main influencing parameters concerning the thermal conditions within the composite casting region could be pointed out. Finally, basic guidance is given for the design of an appropriate composite mould system.
Abstract: Equal Channel Angular Pressing (ECAP) is currently
being widely investigated because of its potential to produce ultrafine
grained microstructures in metals and alloys. A sound
knowledge of the plastic deformation and strain distribution is
necessary for understanding the relationships between strain
inhomogeneity and die geometry. Considerable research has been
reported on finite element analysis of this process, assuming threedimensional
plane strain condition. However, the two-dimensional
models are not suitable due to the geometry of the dies, especially in
cylindrical ones. In the present work, three-dimensional simulation of
ECAP process was carried out for six outer corner radii (sharp to 10
mm in steps of 2 mm), with channel angle 105¶Çü▒, for strain hardening
aluminium alloy (AA 6101) using ABAQUS/Standard software.
Strain inhomogeneity is presented and discussed for all cases. Pattern
of strain variation along selected radial lines in the body of the workpiece
is presented. It is found from the results that the outer corner
has a significant influence on the strain distribution in the body of
work-piece. Based on inhomogeneity and average strain criteria,
there is an optimum outer corner radius.
Abstract: The present work analyses different parameters of pressure die casting to minimize the casting defects. Pressure diecasting is usually applied for casting of aluminium alloys. Good surface finish with required tolerances and dimensional accuracy can be achieved by optimization of controllable process parameters such as solidification time, molten temperature, filling time, injection pressure and plunger velocity. Moreover, by selection of optimum process parameters the pressure die casting defects such as porosity, insufficient spread of molten material, flash etc. are also minimized. Therefore, a pressure die casting component, carburetor housing of aluminium alloy (Al2Si2O5) has been considered. The effects of selected process parameters on casting defects and subsequent setting of parameters with the levels have been accomplished by Taguchi-s parameter design approach. The experiments have been performed as per the combination of levels of different process parameters suggested by L18 orthogonal array. Analyses of variance have been performed for mean and signal-to-noise ratio to estimate the percent contribution of different process parameters. Confidence interval has also been estimated for 95% consistency level and three conformational experiments have been performed to validate the optimum level of different parameters. Overall 2.352% reduction in defects has been observed with the help of suggested optimum process parameters.
Abstract: End milling process is one of the common metal
cutting operations used for machining parts in manufacturing
industry. It is usually performed at the final stage in manufacturing a
product and surface roughness of the produced job plays an
important role. In general, the surface roughness affects wear
resistance, ductility, tensile, fatigue strength, etc., for machined parts
and cannot be neglected in design. In the present work an
experimental investigation of end milling of aluminium alloy with
carbide tool is carried out and the effect of different cutting
parameters on the response are studied with three-dimensional
surface plots. An artificial neural network (ANN) is used to establish
the relationship between the surface roughness and the input cutting
parameters (i.e., spindle speed, feed, and depth of cut). The Matlab
ANN toolbox works on feed forward back propagation algorithm is
used for modeling purpose. 3-12-1 network structure having
minimum average prediction error found as best network architecture
for predicting surface roughness value. The network predicts surface
roughness for unseen data and found that the result/prediction is
better. For desired surface finish of the component to be produced
there are many different combination of cutting parameters are
available. The optimum cutting parameter for obtaining desired
surface finish, to maximize tool life is predicted. The methodology is
demonstrated, number of problems are solved and algorithm is coded
in Matlab®.