Applied Mechanics and Materials Vol. 787

Abstract: Fiber reinforced plastics are composite materials made of polymer matrix reinforced with fibers. Fiber reinforced plastics find increased applications in automotive, marine, aerospace and construction industries. The objective of the present work is to study the effect of nano aluminum oxide fillers on the properties of glass fiber reinforced plastics. The glass fiber reinforced plastic specimens were manufactured with glass fiber chopped strand mat, polyester resin and nano aluminum oxide fillers by the hand layup technique. The nano aluminum oxide fillers are incorporated in different weight ratios in the fiber reinforced plastics and the mechanical properties were evaluated.

Abstract: Aluminum alloy (AA2014) matrix composites reinforced by different weight percentage of aluminum oxide (Al₂O₃) in micro and nano sizes were fabricated through powder metallurgy route followed by hot extrusion process. Seven different aluminium composites with varying percentages of nano and micron sized alumina particles varying from 1% to 10% were evaluated in addition to monolithic alloy. The microstructure of nano-composite and monolithic alloys were examined by optical microscope and scanning electron microscope (SEM) equipped with an energy dispersive X-ray analysis (EDAX). In addition, the effects of weight fraction of the reinforcement matrix on mechanical properties were evaluated. The results have indicated that, a significant improvement in hardness of the nano composite was found in case of nano-composite with 8% of micro Al₂O₃ and 2% of nano Al₂O₃ particles by the addition of reinforcement.

Abstract: A high density nanoscale clusters of Y–Ti–O exhibit superior creep strength and potential for high resistance to radiation damage. X-Ray Diffraction is used to determine the formation of the complex nanoclusters (NCs). The formation of Y₂TiO₅ NCs takes place during heat treatment of mechanically milled (MM) titanium and Yttria, and also it forms the mixture of Y₂Ti₂O₅ and Y₂Ti₂O₇ NCs during the high temperature soaking of MM iron, MM titanium and yttria. The microstructure of the hot consolidated mixture of MM iron, MM titanium and yttria were obtained through scanning electron microscopy (SEM). The back scattered electron mode is used to show the contrast between different elements in the microstructure. The increase in soaking temperature increases the size of the nanocluster, which decrease the volume fraction and number densities. A large population of nanoclusters precipitates during the heat treatment at high soaking temperature.

Abstract: An attempt is made to mitigate wear in cast magnesium alloy by incorporating flyash reinforcement on the surface through friction stir processing. Wear resistance is evaluated using pin-on-disc wear testing. Effect of dry sliding wear process parameters such as speed, time and distance were studied by using design of experiments. Empirical relationships were established between the process parameters and wear resistance of base metal as well as surface composite. Further, wear map is constructed using graphical optimization technique, which can be used to predict the lower and upper bound of wear rate for the both base metal and friction stir processed surface composites under dry sliding condition.

Abstract: Fiber Reinforced Plastics are now being used in all fields of industry as well as for consumer durables. In the present work, FRP laminates of glass/PP fabricated by film stacking method are studied for various mechanical properties. The glass/PP laminate of required thickness (3-4 mm) is fabricated by stacking a number of FRTP prepregs in the mould and applying heat and pressure in compression moulding press. Dynamic Mechanical Analysis, tensile, flexural and izod impact tests were performed on FRTP laminates. From DMA test, the following viscoelastic properties of GF/PP laminate were observed. (i) The storage modulus increases with increasing fibre volume fraction. (ii) The loss factor decreases with increase in volume fraction. Tensile strength and flexural strength values increase with increase in fibre volume fraction. Impact strength decreases with increase in fibre volume fraction. The results of the present study will be useful in determining the end use applications of FRTP laminates in industry.

Abstract: By considering several applications of aluminum based particle reinforced composites especially in automobile, aerospace and electronic industries, in this work, prediction of machinability responses of A356 alloy-SiC particles (5, 10, 15 and 20 vol%) reinforced metal matrix composites is described. Composites were synthesized by vacuum hot pressing (VHP) assisted powder metallurgy (P/M) process. Effect of cutting speed (Vc), feed (f), depth of cut (d) and quantity of SiC (vol %) on machinability of composites in terms of material removal rate (MRR) and resultant cutting forces (F_R) during end milling were investigated. Milling experiments were carried in dry condition based on central composite design and KISTLER dynamometer was used to measure cutting forces. Resultant cutting force values were increased from 21 to 105 N with an increase in ‘f’ and ‘d’, but decreased with increase in ‘Vc’. Increase in machining parameters increased the MRR from 2.3 to 8.6 × 10³ mm³/min and increase in SiC reduced the MRR. Statistical modeling with cubic response equations were used to predict the results and predicted results were closely matching with experimental values.

Abstract: Metal matrix composites (MMC) are the combination of base metal matrix and reinforcing materials like SiC, Al₂O₃, etc. The present research is focused on the machinability studies of Al 6061 reinforced with 10% wtof Al₂O₃ particles using multi layered coated carbide inserts. Fabricated samples by stir casting route were turned by the most variable factors, cutting speed, depth of cutand by a constant feed rate of 0.206 mm/rev. Surface roughness and tool wear are considered asoutput. Experiments are conducted by varying the cutting speed while keeping feed rate and depth of cut as constant. After the optimum cutting speed was determined, the depth of cut is varied by keeping the cutting speedand feed rateas constant.Based on the optimum cutting speed (150 m/min), depth of cut (1.2 mm) and feed rate (0.206 mm/rev), a long run test was carried out to find out the tool life and surface finish. But due to the softness nature built up edge formation is obtained. At the optimal parametric combination, the built up edge obtained is less than 2 mm for a machining time of 425 s

Abstract: Aluminum alloy 6061 reinforced with 1.0 weight percentage of Silicon Carbide (SiC) nanoparticles were fabricated using the novel ultrasonic cavitation assisted stir casting approach. Three types of nanoparticle feeding mechanisms were attempted for fabricating the metal matrix nanocomposites. The fabricated nanocomposites were subjected to tension test, hardness test and scanning electron microscopic analysis. From the tested results, it was found that feeding the particles using Al foils followed by ultrasonic cavitation proved as a suitable method for obtaining the better mechanical properties of the fabricated nanocomposites. Scanning electron microscopy analysis confirmed the uniform dispersion SiC in Al matrix by capsule feeding method. Energy dispersive spectroscopy validates the incorporation of SiC in Al matrix.

Abstract: Al6061-TiC in-situ composite was developed using hexafluorotitanate salt and graphite powder. Microstructure studies, hardness and dry sliding friction and wear behavior were investigated for both base alloy and in-situ composite. Friction and wear tests were performed at the normal load and sliding speeds in the range 20-100N and 0.314-1.57m/s respectively. For a given TiC content, coefficient of friction was lower than base alloy for all the loads and sliding speeds. A tremendous improvement in the wear resistance of the composite was found when compared with base alloy.

Abstract: An Investigation was carried out to study the effect of red mud reinforcement in Al-6Si-0.45Mg alloy (A356) for improving hardness, wear rate and co-efficient friction. The red mud 53 micron size particles collected from MALCO, Mettur, Tamil Nadu, India, was preheated in a furnace to 500^o C and mixed with molten Al-6Si-0.45Mg alloy to make the composite specimens. Al-6Si-0.45Mg alloy-red mud composite specimens were manufactured by stir casting technique using Al-6Si-0.45Mg alloy as matrix and reinforced with 5%, 10%, 15% and 20% volume percentages red mud as the reinforcement. The Al-6Si-0.45Mg alloy–red mud composite specimens were T6 heat treated to improve the mechanical properties. The artificial aging time and aging duration were varied to study their effect on mechanical properties of the composites. Then the specimens hardness, wear rate and coefficient of friction were tested as per ASTM standards. It was found that the hardness increased when the red mud content was increased in the base alloy at all the heat treatment conditions. The peak age timing which gives highest hardness was found to decrease with increased red mud content. The wear rate was decreased when the hardness was increased. The effect of solution treatment and artificial aging on the microstructure was also studied by microscopy.