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In this experimental work, AA7075-15 wt. % SiC (10–20 µm) composite was made through stirring casting. Experiments were performed on this composite by tungsten carbide cutting tools of different no...

Silicon carbide (SiC), Silicon nitride (Si3N4) particles were added in AA6082 to produce aluminum matrix composites (AMCs). Identifying suitable joining process and selecting appropriate parameters is essential for application of these AMCs. Fabricated plates of AA6082/SiC/5 wt.%, AA6082/SiC/10 wt.%, AA6082/SiC/15 wt.% and AA6082/Si3N4/5 wt.%, AA6082/Si3N4/10 wt.%, AA6082/Si3N4/15 wt.% composites were properly welded by friction stir welding (FSW). L9 orthogonal array of taguchi was utilised to design the experiments and optimize the parameters. Effects of tool rotation speed, welding speed, and tool tilt angle on hardness of weld nugget zone of AA6082/SiC composites and AA6082/Si3N4 composites were also investigated. Homogeneous spreading of SiC particles in addition to spherodization of silicon needles and their spreading through matrix were found to be dominant factors for property improvement in stirring zone. It was revealed that the hardness of FSW joints increases because of existence and pining effect of hard Si3N4 particles. It was detected that increase in micro hardness of weld nugget of AA6082/SiC composite was more, as compared to increase in micro hardness of AA6082/Si3N4 composites. Novelty of work is that FSW parameters have been optimized to successfully weld and achieve maximum hardness of AA6082/SiC and AA6082/Si3N4 composites. Findings of this research work will be utilized for FSW of components made of these composites, and to achieve maximum hardness of FSW joints. Such components will be utilized in aeroplanes, satellite, cars and ships.

Metal matrix composites (MMCs) possess high specific strengths and resistance to wear and deformation. Because of these properties, they are needed for automotive and aerospace uses. SiC-reinforced MMCs show good prospective for these uses, but their greater use is hindered by inadequate ductility and fabrication problems. These issues need to be resolved. AA7075 was provided with 10 wt.% and 15 wt.% SiC particle size of 10–20 μm and 20–40 μm by stir casting technique. Composite casting was fabricated. Samples were prepared from these castings. Samples were examined utilizing scanning electron microscopy (SEM) and energy-dispersive X-ray analyses (EDAX). SiC particle distribution and interaction with AA7075 matrix was studied. Change in hardness and tensile strength due to addition of different wt.% and particle size of SiC particles was also investigated. Microstructures of all four types of AA7075/SiCp composite exhibited uniform SiCp dispersal into AA7075. Hardness enhanced by 10.48% with rise of SiC reinforcement from 5 to 15%. Maximum improvement (9.67%) in tensile strength was seen with the addition of 10 wt.% SiC (10–20 μm) particles. AA7075/SiCp composites will be used in industrial applications requiring high tensile strength along with wear resistance.

Turning of 7075 Al alloy reinforced with SiC particulates was done on CNC machine by using tungsten carbide tools. Experimental were planned as per face centered central composite design (FCCCD). Response surface methodology (RSM) was utilized for modeling impact of parameters viz. cutting speed, feed, depth of cut and nose radius on responses viz. surface roughness and tool life. Single objective optimization for surface roughness and tool life was carried out. To obtain balance between surface roughness and tool life, a system for concurrent optimization of several objectives founded on an overall desirability function was utilized. Multi response optimization provided cutting speed of 90 m/min, feed of 0.15 mm/rev, depth of cut of 0.20 mm and nose radius of 0.68 mm. turning at these conditions will result in lowest surface roughness and maximum tool life. Which signify a satisfactory whole desirability. Components of AA7075/ SiC composite are being used in automobiles, ships, aero planes due to their high specific strength and wear resistance. Machining of AA7075/10 wt.% SiC (10-20 μm) composites is still a challenge due to poor surface roughness and high tool wear. Novelty of this work is that values of parameters to simultaneously achieve minimum surface roughness and maximum tool life was obtained by multi response optimization of process parameters. Very little research is available on this issue in literature.

Supplemental material, sj-docx-1-tdo-10.1177_00494755211056170 for Methotrexate in erythema nodosum leprosum: Pitfalls to avoid by Hitaishi Mehta, Tarun Narang, Sunil Dogra and Bhushan Kumar in Tropical Doctor

Supplemental material, sj-docx-1-tdo-10.1177_00494755211056170 for Methotrexate in erythema nodosum leprosum: Pitfalls to avoid by Hitaishi Mehta, Tarun Narang, Sunil Dogra and Bhushan Kumar in Tropical Doctor

PurposeMechanical properties are highly sensitive to the microstructure, and these are indirectly related to solidification parameters and processing conditions. AA7075 possesses lightweight and excellent properties as structural material which can be optimized with SiCp addition and a good fabrication technique.Design/methodology/approach7000 series aluminium alloys exhibit the highest mechanical properties. They are used for high-strength structural applications such as aircraft parts and sporting goods. The desirable properties of these alloys are: low density, high stiffness, specific strength, good wear resistance and creep resistance. The focus of this work is to investigate the microstructure of composites formed by the dispersion of silicon carbide particles (SiC) into AA7075 by stir casting processes. 7075 Al alloy is reinforced with 10 and 15 wt.% SiCp of size 10–20 µm by stir casting process. The composites have been characterized by X-ray diffraction and scanning electron microscopy, differential thermal analysis and electron probe microscopic analysis.FindingsSiCp distribution and interaction with AA7075 matrix have been studied. AA7075/10 wt.%/SiCp (10–20 µm) and AA7075/15 wt.%/SiCp (10–20 µm) composites microstructure showed excellent SiCp distribution into AA7075 matrix. In addition, no evidence of secondary chemical reactions has been observed in X-ray diffraction and electron probe microscopic analysis.Originality/valueLittle experimental work has been reported so far about effect of addition of 10 and 15 wt.% SiCp of size (10–20 µm) on the microstructure of 7075 Al alloy fabricated by stir casting process. The present investigation has been carried out to study the microstructure and carry out XRD, DTA and EPMA analysis of 7075 Al alloy, 10 and 15 wt.% SiCp of size (10–20 µm) composite and detect the interfacial reactions with the objective to minimize the formation of Al4C3.

Machining experiments on 7075 Al alloy/10 wt% SiC (particle size 10–20 µm) have been conducted based on response surface methodology (RSM). Sequential approach using face-centred central composite ...

Femur bone is both strongest and longest bone in human body. This bone is contained linear elastic, isotropic and homogeneous material of calcium phosphate. It supports maximum weight of the body in between hip and knee joint during static loading condition. Femoral shaft fractures are common in both the young and elder people in India due to high accident rate and osteoporosis respectively. This major problem can be indirectly reduced by using locking compression plates which is most preferable now. The locking plate possess several advantages in fracture fixation, combining angular stability through use of locking screws with misalignment correction and fracture reduction into the plate through use of suitable screws. The mechanical analysis of different material which are suitable for femoral locking plate need to be workout, Because uniformity of stress transfer to the bone along with femoral locking plate is also important. As expected, stresses can be found at screw holes, nearest to the fracture site. This design modification can reduce the clearance of screw which results in permanent stability of femoral locking plate and the use of this different material will help us to find suitable biomaterial for femoral locking plate. Novelty of this research work is that the proposed design modification will substantially increase the fatigue life of the fixator, especially at screw holes nearest to the fracture region, where most fatigue fractures are known to occur and will consequently be function of greater fracture load

Purpose Sound microstructure components are necessary for reliability and safety; hence, these components are used in aircraft, satellite, automobiles and ships, where many commercial alloys are not suitable. The paper aims to discuss this issue. Design/methodology/approach AA6082/Si3N4 and AA6082/SiC composites were fabricated using the stir-casting process considering 5, 10 and 15 vol.% of reinforcement particles. Density and porosity of AA6082/Si3N4 and AA6082/SiC composites were calculated. Characterization was done using an X-ray (EDX) detector, attached to SEM. The effect of addition of Si3N4 and SiC particulates in the AA6082 was investigated. Findings Results showed that Si3N4 and SiC particulates had good wettability with AA6082 and were uniformly distributed in AA6082 matrix. No adverse effects of reactions were noticed in the microstructure of AA6082/Si3N4 and AA6082/SiC composites. Research limitations/implications AA6082 with more than 15 vol.% of Si3N4 and AA6082/SiC reinforcement particles do not find industrial application where high hardness and tensile strength are required. Practical implications Components made from AA6082/Si3N4 and AA6082/SiC composites find their application where high hardness with better tensile strength is required. Social implications Naturally and locally available materials are utilized for fabrication. Originality/value Little work is available in the literature on fabrication and characterization of AA6082/Si3N4 and AA6082/SiC composites. The authors have identified the process parameters at which proper fabrication is done and sound microstructure is obtained.

Weldability, microstructure evolution and tensile strength of an aluminium alloy (AA6082) and of two category of composites with AA6082 matrix reinforced with Si3N4 and SiC particles during friction stir welding (FSW) were investigated. 5, 10 and 15 weight percentage of reinforced particle were used in each category. FSW was carried out as per the parameters selected by Taguchi L-9 orthogonal Array. Microstructure of nugget region was investigated by scanning electron microscopy (SEM) and EDS analysis. Effect of tool rotational speed, welding speed and tool tilt angle on tensile strength was also investigated. The optimum parameters to get maximum ultimate tensile strength (UTS) for AA6082/SiC and AA6082/ Si3N4 composites were found out. On one hand, SiC particles are fractured thus fined due to intensive stirring action during FSW. On the other hand, the plastic flowing of material in the weld is benefit to eliminate microporocities existed in original base material. The highest tensile strength of 193 MPa was obtained for AA6082/15 wt% Si3N4 composite, at tool rotation speed of 1950 rpm at fixed welding speed of 40 mm/min and fixed tool tilt angle of 2°. Hard Si3N4 particles transfer their strength to the AA6082 matrix by their strengthening mechanism. This happens because of load transfer from Si3N4 particles to AA6082 matrix.

Many researchers are doing effort to investigate the effect of different particulates or fillers incorporated in the composite materials. In this investigation, the effect of the incorporation of different amounts of carbon black particulates on the mechanical performance of carbon fiber-reinforced epoxy composites has been studied. The carbon fiber-reinforced carbon black/epoxy hybrids were prepared with keeping constant weight fraction of carbon fiber and varying weight fraction of carbon black (0, 5, 10, and 15 wt%), using hand lay-up technique. After cure, the fabricated composite materials were cut and dimensioned into specimens as per the ASTM standards of testing and submitted to tensile, flexural, and impact tests. The microstructural characteristics and fracture surfaces of the composite were examined by scanning electron microscope (SEM). Increments of 65.78, 32.07, and 36.11% have been noticed in the tensile strength, flexural strength, and impact strength respectively for the hybrid composite (10 wt% carbon black) with respect to the conventional carbon fiber-reinforced epoxy composite. The experimental result has been validated with the numerical technique. This study represents that carbon black/epoxy composites reinforced with carbon fiber show higher mechanical performance than the conventional carbon fiber-reinforced epoxy matrix composites.

Green manufacturing demands least wastage. Minimum chip formation reduces adverse effect on environment. Nose radius has a major role in reducing development of chips. Selection of proper nose radius and machining parameters will reduce amount of chip, therefore protect the environment. In finish turning of Al alloy-SiC, nose radius wear mainly affect the surface feature of the final product. It is owing to the direct contact between the area of tool nose and the SiC particles during turning. This paper is focused on influence of tool nose radius and machining parameters on surface quality of AA7075/15 wt.% SiC (20 - 40 μm) composites and tool life of tungsten carbide inserts while dry turning. Response surface method (RSM) was utilized to find the roughness and tool life under numerous turning situations. Considering the single objective optimization of turning parameters, minimum roughness of 2.088 μm, was achieved at nose radius of 1.2 mm and maximum tool life of 6.72 min, was obtained at nose radius of 0.4 mm. Multi objective optimization by desirability analysis for minimum roughness and the maximum life of tool has shown that suitable value of nose radius is 0.4 mm. Multi objective optimization of both roughness of surface and life of tool results in 1.81% increase in surface roughness and 10.11% decrease in tool life. Abrasion was mainly found to be responsible for wear of tungsten carbide inserts, while turning of AA7075/15 wt.% SiC (20 - 40 μm) composites. Novelty of this research work is that so far no one has investigated impact of nose radius and machining parameters on surface roughness, tool wear and tool life during turning of AA7075/15 wt.% SiC composites. Outcome of this research work will be useful for vehicle, aeroplane, space and ship industry.

Friction stir welding (FSW) of 6-mm-thick plates of AA6061-T651 was carried out using a simple cylindrical pin tool. The impact of welding factors (rotational speed, welding speed) on tensile properties, microhardness, and surface roughness of FSW joints was investigated. Ultimate tensile strength (UTS), yield strength, and % elongation of AA6061-T651 base plate as well as FSW joints were found out using a universal testing machine (UTM). Maximum value of UTS and yield strength were achieved at rotational speed of 1400 rpm and welding speed of 20 mm/min. Minimum surface roughness was reached at rotational speeds of 1400 rpm and welding speed of 20 mm/min. Microstructural evolutions in the friction stir welded (FSWed) joint and microhardness profile were also determined. Maximum hardness of HV 120 was acquired for the stir zone (SZ). Hence, attainment of the maximum tensile strength, microhardness, and minimum surface roughness during FSW is a desired method to improve the service life and suitability of AA6061-T651.

The original version of this paper was unfortunately published with an error in the order of authors and their corresponding affiliations. The correct data is shown above.

Reducing the energy consumption during machining of metal matrix composites (MMC) can significantly improve the environmental performance of manufacturing systems. To achieve this, calculation of energy consumption in the computerized numerical controlled (CNC) turning machine is required. It is important to minimize the power consumption and maximize tool life during machining operations, being performed on the CNC turning machine. However, this is challenging due to complexity of manufacturing systems and the nature of material being machined. This paper presents the findings of experimental investigations into the effects of cutting speed, feed rate, depth of cut and nose radius in CNC turning of 7075 Al alloy 15 wt% SiC (particle size 20–40 μm) composite. Design of experiment techniques, i.e. response surface methodology (RSM) has been used to accomplish the objective of the experimental study. The machining parameters such as cutting speed, feed rate, depth of cut and nose radius are optimized by multi-response considerations namely power consumption and tool life. A composite desirability value is obtained for the multi-responses using individual desirability values from the desirability function analysis. Based on composite desirability value, the optimum levels of parameters have been identified, and significant contribution of parameters is determined by analysis of variance. Confirmation test is also conducted to validate the test result. It is clearly shown that the multi-responses in the machining process are improved through this approach. Thus, the application of desirability function analysis in response surface methodology proves to be an effective tool for optimizing the machining parameters of 7075 Al alloy 15 wt% SiC (20–40 μm) composite. Result of this research work show that when turning is be carried out at values of machining parameters obtained by multi response optimization through desirability analysis route this will reduce power consumption by13.55% and increase tool life by 22.12%.

7075 aluminum (Al) alloy as matrix and silicon carbide (SiC) as reinforcement has been identified since it has potential applications in aircraft and space industries because of lower weight to strength ratio, high wear resistance and creep resistance. Thorough investigations about the microstructure and characterization of Al alloy/SiC composite are needed so that metal matrix composites (MMCs) fabricated for aircraft and space industries are defect free and have sound microstructure. Objective of this research work are the fabrication and microstructural investigations of AA7075–SiCp MMCs. 7075 Al alloy is reinforced with 10 and 15 wt.% SiCp of size 20–40 μm by stir casting process. The resulting as-cast composite structures are analyzed using scanning electron microscopy, X-ray diffraction (XRD), differential thermal analysis, and electron probe microscopic analysis (EPMA). SiCp distribution and interaction with 7075 Al alloy matrix is studied. The 7075 Al alloy–SiCp composite microstructure showed excellent SiCp distribution into 7075 Al alloy matrix. In addition to this, no evidence of secondary chemical reactions is observed in XRD and EPMA analysis. Decomposition step in derivative thermogravimetric curve is seen at temperature of 1,257, 1,210, and 1,256 °C for 7075 Al alloy, AA7075/10 wt.%/SiCp (20–40 μm) and AA7075/15 wt.%/SiCp (20–40 μm) composites, respectively. So, these composites can be successfully used for applications where temperature does not exceed beyond 1,250 °C.

Experiments were carried out using carbide turning inserts on AA7075/10 wt.% SiC (particle size 10-20 μm) composites to get actual input values to the optimization problem, so that the optimized results are realistic. By using experimental data, the regression model was developed. This model was used to formulate the fitness function of the genetic algorithm (GA). This investigation attempts to perform the application of GA for finding the optimal solution of the cutting conditions minimum value of surface roughness. The analysis of this investigation shows that the GA technique is capable of estimating the optimal cutting conditions that yield the minimum surface roughness value. With the highest speed, the lowest feed rate, the lowest depth of cut, and the highest nose radius of the cutting conditions' scale, the GA technique recommends 1.039 μm as the best minimum predicted surface roughness value. This means that the GA technique has decreased the minimum surface roughness value of the experimental sample data, regression modeling and desirability analysis by about 3%, 1%, and 2.8%, respectively.

The stir casting method was used for fabrication of 7075 aluminum alloy with 10 wt.% SiC particles of size 20-40 μm. The research objective of this paper are to achieve uniform distribution of SiC particles in the 7075 aluminum alloy matrix, characterization, and analysis of mechanical properties of composite formed. Experiments were carried out at stirring speeds of 500, 650, 750 rpm, and stirring period of 10 min. Microstructures of aluminum alloy and composites with 5, 10 wt.% SiC reinforcements were examined. The results reveal that composite produced at stirring speed of 650 rpm and stirring time of 10 min has uniform distribution of SiC particles. XRD and EDAX analysis were carried out for 7075 Al alloy and composite with 10 wt.% SiC reinforcement. No adverse reaction was observed in XRD and EDAX of composite with 10 wt.% SiC reinforcement. Tensile strength and hardness increased by 12.74% and 10.48%, respectively, with the increase in percentage of SiC reinforcement from 5 to 15 wt.%.

In the present study, an attempt has been made to investigate the influence of cutting speed, depth of cut, and feed rate on surface roughness during machining of 7075 Al alloy and 10 wt.% SiC particulate metal-matrix composites. The experiments were conducted on a CNC Turning Machine using tungsten carbide and polycrystalline diamond (PCD) inserts. Surface roughness of 7075Al alloy with 10 wt.% SiC composite during machining by tungsten carbide tool was found to be lower in the feed range of 0.1 to 0.3 mm/rev and depth of cut (DOC) range of 0.5 to 1.5 mm as compared to surface roughness at other process parameters considered. Above cutting speed of 220 m/min surface roughness of SiC composite during machining by PCD tool was less as compared to surface roughness at other values of cutting speed considered. Wear of tungsten carbide and PCD inserts was analyzed using a metallurgical microscope and scanning electron microscope. Flanks wear of carbide tool increased by a factor of 2.4 with the increase of cutting speed from 180 to 240 m/min at a feed of 0.1 mm/rev and a DOC of 0.5 mm. On the other hand, flanks wear of PCD insert increased by only a factor of 1.3 with the increase of cutting speed from 180 to 240 m/min at feed of 0.1 mm/rev and DOC 0.5 mm.

BACKGROUND In this study, the efficacy of oral aspirin vs. topical aspirin in moisturizer (Vaseline Intensive Care Lotion) was studied in an open, randomized, parallel trial in patients with acute herpetic neuralgia. METHODS Thirty patients were evaluated in the trial, with 15 in each group. The patients were randomized to receive either oral aspirin, 375-750 mg three times a day, or 75 mg topical aspirin/mL of moisturizer (5-10 mL, depending on the extent of involvement), three times a day, for 21 days. Pain was assessed daily by means of a self-rating visual analog scale and physician assessment. In addition, the skin and plasma levels of aspirin were measured in both groups. RESULTS The mean time to onset of pain relief was 44 min with topical aspirin and 110 min with oral aspirin. The mean duration of pain relief after a single application of topical aspirin was 5.4 h, whereas it was 3.5 h with oral aspirin. The mean visual analog scale scores for pain with oral aspirin decreased from 68.2 +/- 6.1 on day zero to 43.1 +/- 8.7 on day 21, which was not significant compared with the baseline score. With topical aspirin, the baseline pain score was 77.5 +/- 3.7 and decreased to 6.8 +/- 3 on day 21 (P < 0.001 compared to the baseline score and compared to oral aspirin). The mean plasma and skin levels of aspirin following oral administration were 16.21 +/- 1.1 microg/mL and 1.97 +/- 0.3 microg/mm2, respectively. After topical administration, the mean plasma level of aspirin was 2.29 +/- 0.5 microg/mL (P < 0.01 vs. oral aspirin) and the skin level was 5.96 +/- 0.4 microg/mm2 (P < 0.05 vs. oral aspirin). Treatment tolerance was excellent in both groups. CONCLUSIONS This trial has demonstrated that topical aspirin in moisturizer is clearly superior to oral aspirin in relieving the pain of acute herpetic neuralgia, and that the analgesic activity of aspirin is largely due to its local effect.

Optimization in turning means determination of the optimal set of the machining parameters to satisfy the objectives within the operational constraints. These objectives may be the minimum tool wear, the maximum metal removal rate (MRR), or any weighted combination of both. The main machining parameters which are considered as variables of the optimization are the cutting speed, feed rate, depth of cut, and nose radius. The optimum set of these four input parameters is determined for a particular job-tool combination of 7075Al alloy-15 wt. % SiC (20–40 μm) composite and tungsten carbide tool during a single-pass turning which minimizes the tool wear and maximizes the metal removal rate. The regression models, developed for the minimum tool wear and the maximum MRR were used for finding the multiresponse optimization solutions. To obtain a trade-off between the tool wear and MRR the, a method for simultaneous optimization of the multiple responses based on an overall desirability function was used. The research deals with the optimization of multiple surface roughness parameters along with MRR in search of an optimal parametric combination (favorable process environment) capable of producing desired surface quality of the turned product in a relatively lesser time (enhancement in productivity). The multi-objective optimization resulted in a cutting speed of 210 m/min, a feed of 0.16 mm/rev, a depth of cut of 0.42 mm, and a nose radius of 0.40 mm. These machining conditions are expected to respond with the minimum tool wear and maximum the MRR, which correspond to a satisfactory overall desirability.

Dyschromatosis universalis hereditaria is a common disorder in Japan. We report a case in an Indian woman with no family history of the disorder.

Patch test was evaluated for the identification of causative agent in cutaneous eruptions due to antiepileptics. Patch tests were carried out in twenty patients and ten controls with carbamazepine, phenytoin sodium, phenobarbitone and sodium valproate. Sodium valproate was found tobe irritant in 1 and 5% concentration and further dilution is recommended for patch testing. Patch test was positive in 14 (70%) patients and in 7 with suspected drug alone, and remaining 7 were positive with more than one antiepileptic drug. We recommended patch test for identification of causative drug in rashes due to antiepileptics.

Autologous transplantation of melanocyte/melanocytes bearing epidermis for vitiligo can be done by mini-punch grafting (MPG), suction blister epidermal grafting (SBEG), thin split -thickness skin grafting (TSTG), transplantation of basal cell layer enriched suspension and cultured epithelial/melanocyte transplantation. To date no comparative study of these transplantation procedures has been published. Comparison of different studies carried out at different centers may be difficult in the absence of uniform evaluation criteria. In most of the published studies, the results were evaluated in terms of extent of pigmentation. Complictions and color match were evaluated separately. This approach, however, may not give a fair idea about the results. We have developed a scoring system with holistic approach considering the extent of pigmentation, color match and the complications of both the donor and the recipient areas, all taken together. In the scoring system, the score for individual criteria was multiplied with a factor, the value of which was decided on the basis of relative importance of each criteria. The use of this scoring system is exemplified in twelve patients who underwent TSTG, SBEG and MPG. In the scoring system the results were judged as excellent and fair in 3 patients each, as good in 4 patients and as poor in 2 patients.

Three women with large, mutilating genital ulcers of long duration, destroying almost the lower half of the external genitalia, are reported. They had a history of recurrent oral ulcers as well. All patients had been diagnosed as having ′genital ulcer syndrome′ in the past and had been treated with antimicrobials. Histopathology of the biopsy from the margin of the ulcer revealed features of leukocytoclastic vasculitis. Considering the history, clinical features and histology, a diagnosis of bipolar aphthosis was made in all patients. All patients responded well to immunosuppressive therapy. The cases are reported because of the presence of genital ulcers of an unusually large size, mutilating character and their close similarity to genital ulcers due to sexually transmitted diseases, especially genital herpes and donovanosis.

Metallic composite materials reinforced with ceramic particles or short fibres, also known as discontinuously reinforced metal matrix composites (MMCs), have been studied over the past few decades. There is a strong potential for these materials to replace existing metallic systems due to their enhanced mechanical properties (especially higher specific stiffness and strength). Performance of automobile and aircraft parts can be improved through either a reduction in absolute weight or an increase in strength to weight ratio. 7075 Al alloy reinforced with 10 vol. % SiC particles of size 20 to 40 μm was prepared by using stir casting process. The values of Young's modulus and peak frequency for 7075 Al alloy and 10% SiC composite were found out by using dynamic elastic property analyser. Porosity of 10% SiC composite was also calculated. Test results indicate that value of Young's modulus and peak frequency for composite increases 24.898% and 7.38% respectively on average. This is due to addition of 10% SiC particles. The porosity of composite is found to be 3.16%.

In the present paper Taguchi's Methodology has been applied to the Vacuum Assisted Evaporative Pattern Casting (VAEPC) process of Al-7%Si alloy to determine the most influential control factors. In order to evaluate the effect of process parameters such as grain fineness number, time of vibration, degree of vacuum and pouring temperature on percent deviation of VAEPC process castings, the Taguchi parameter design and optimisation approach is used. The results indicate that the grain fineness number, time of vibration, and degree of vacuum are significant. The predicted optimal value of % deviation of castings produced by the VAEPC process is 0.4172.

In this paper an attempt has been made to achieve a set of values of stir casting process variables that may yield optimum porosity to the 7075 Al alloy with 10% SiC composite. The effect of selected process variables on the porosity of 7075 Al alloy 10% SiC composite and subsequent optimal settings of the variables have been obtained using Taguchi method. The results indicate that the holding time, holding temperature and stirring speed are the significant variables. Stirring time is insignificant variable. As the holding time, holding temperature and stirring time increases the porosity decreases. When the stirring speed increases, porosity increases. The predicted optimal value of porosity is 4.71%.