Applied Mechanics and Materials Vols. 813-814

Abstract: Poly-ether-ether-ketone (PEEK) becomes one of the most promising polymer material for the tribological applications because of its outstanding performance such as high mechanical properties, high chemical resistance, and high wear resistance. The present work is focused on optimization of dry sliding wear parameters of MWCNT reinforced PEEK matrix composites using RSM based desirability approach. The materials used for the present investigation are unreinforced PEEK and reinforced with 0.5% and 1% MWCNT. Wear parameters such as load, sliding speed and % of MWCNT are chosen as control factors to optimize the wear loss and coefficient of friction. An experimental plan of a L₉ based on Taguchi design is employed to carry out the experimental study. After conducting experiment, mathematical models have been developed to fit the output responses using Response surface methodology and drilling parameters have been optimized using Desirability based approach. This methodology deals with the development of modelling equations for each response. The relative significance of the various parameters has been found using ANOVA.

Abstract: Silver doped cadmium sulphide nanocrystallites (CdS:Ag), undoped cadmium sulphide nanocrystallites (CdS), have been synthesized by the chemical precipitation method. Nanocrystalline materials are confirmed by the scanning electron microscopy method. The presented elements are identified by EDAX (Energy Dispersive X-ray Analysis). X-ray diffraction Method (XRD) is used to calculate the average size of the prepared sample. Morphological studies (SEM) are used to analyse the nature of the sample. The results are reported in this paper.

Abstract: The present investigation involves studying the mechanical properties of the fabricated aluminium 7075 hybrid metal matrix composites reinforced with various weight % of SiC and Al₂ O₃ particulates by stir casting method. The Al 7075 hybrid metal matrix composites specimen were fabricated using L₉ orthogonal array. The mechanical properties like Brinell Harness (BHN), Rockwell Hardness (HRC) and impact loads were experimented. The mechanical properties like hardness and impact loads have improved with the increase in weight percentage of SiC and Al₂O₃ particulates in the hybrid aluminium matrix.

Abstract: Recently, the polymers and their composites are getting more popular in tribological applications under water condition to replace metallic materials as rubbing materials due to the corrosion problems of the metals. With the outstanding performance such as high mechanical properties, high chemical resistance, and high wear resistance, poly-ether-ether-ketone (PEEK) becomes one of the most promising polymer material for the tribological applications. Carbon nanotubes containing PMCs are being developed and projected for diverse applications in various fields of engineering like automotive, avionic, electronic and bio-medical sectors due to their good tribological, mechanical and thermal properties. In the present investigation, PEEK and PEEK reinforced with MWCNT are synthesized by injection moulding route. Microstructure of MWCNT reinforced PEEK are investigated by Scanning Electron Microscope (SEM). Hence the distribution of reinforcement was noted. The chemical compositions of the different phases were investigated through Energy Dispersive X-Ray (EDX) detector

Abstract: Shape memory materials are stimuli-responsive materials. They are widely used in military, medical, safety, and robotics applications. Until recently, only Ni-Ti based SMA’s are commercially used due to its relatively ease of manufacturing. However, the exorbitantly high cost of Ni-Ti based SMA limits its application to niche markets such as medical stents, aerospace and defence. Recently, it is found that Cu based alloys exhibit shape memory behavior. Out of which, Cu-Al-Be-Mn is most interesting SMA in terms of less process complexity and low cost. Cu–Al–Be-Mn shape memory alloys in the range of 09–15 wt.% of aluminium and 0.1-0.4 wt.% of Beryllium and 0.1 to 0.3 wt.% of Manganese, exhibiting β-phase at high temperatures and manifesting shape memory effect upon quenching to lower temperatures, were prepared through ingot metallurgy. The alloy ingots were homogenized followed by step quenching so as to obtain a structure that is completely martensitic. They were subsequently characterized by X-ray diffractogram (XRD), Differential Scanning Calorimetry (DSC) and Optical Microscope (OM). The shape memory properties of the alloys were studied by bend test. This paper emphasizes the synthesis and characterization of the Cu-Al-Be shape memory alloys.

Abstract: Cu-Al-Be Ternary alloys are prepared by ingot metallurgy route, which exhibits parent phase or Austenite phase at high temperature and Martensite phase at low temperature and also exhibits shape memory effect upon quenching to lower temperature. The Cu-Al-Be SMA was in the range of 10-12wt% of Al and 0.4-0.5 wt% of Be is chosen for present study and different amount of quaternary element is added to the ternary alloy. The variation in shape memory effect, transformation temperature and microstructure is studied by using bend test, differential scanning calorimeter and Optical microscope.

Abstract: This paper envisages to predict the life of an aircraft coating using high strength precipitation hardening 7000 series aluminum alloys, such as 7075 which is used extensively in aerospace industry. Aerospace aluminum alloy 7075 has been researched upon especially for aircraft materials. The intention of protective coating is to save the aerospace aluminium alloy 7075 metal surface from weatherability and, at the same time, to obtain the required degree of cosmetic finish for the object. One was epoxy polyamide as primer layer and other was the polyurethane as top-coat layer of coating through conventional spray type on aluminum alloy 7075 substrates. Epoxy polyamide is useful binders for aircraft primers. Top-coats have also been prepared, but polyurethane is still the choice for aircraft coating. This coating system is typically comprised, of a primer layer and a topcoat layer. The ability of the polyurethane coating is to prevent corrosion, weatherability depends on its anti-corrosive pigments and its adhesion to the substrate. All these factors are widely variable with the geographic location and season such as temperature, wind, oxygen and atmospheric pollutants. The effect of structural and process variable on wear resistance of polyurethane coating was analyzed to determine the maximum wear rate using DOE software optimum samples were prepare according to best level of each factor and its morphology was examined by scanning electron microscope (SEM).

Abstract: Composite materials are important engineering materials due to their outstanding mechanical properties. Composites are materials in which the desirable properties of separate materials are combined by mechanically binding them together. Each of the components retains its structure and characteristic, but the composite generally possesses better properties. Composite materials offer superior properties to conventional alloys for various applications as they have high stiffness, strength and wear resistance. The development of these materials started with the production of continuous-fiber-reinforced composites. The high cost and difficulty of processing these composites restricted their application and led to the development of discontinuously reinforced composites. The aim involved in designing metal matrix composite materials is to combine the desirable attributes of metals and ceramics. The addition of high strength, high modulus refractory particles to a ductile metal matrix produce a material whose mechanical properties are intermediate between the matrix alloy and the ceramic reinforcement. Metal Matrix Composites with Aluminum as metal matrix is the burning area for research now a days.

Abstract: Experimental study on microwave attenuation of ecosand is presented. Ecosand is a by-product of cement industry, and presents good alternative for natural river sand. Ecosand is a composite mixture, primarily containing silica and alumina. Microwave characterization provides good value enhancement for ecosand, encouraging its utilization in construction of EMI shielded buildings including safety vaults, server chambers and critical defense installations. Wave guide based studies on virgin ecosand and ecosand fly ash mixtures are conducted. Varying proportions of ecosand - flyash mixtures are considered. Reflected and transmitted power levels are measured. The preliminary results provide satisfactory EMI characteristics for a 60-40 ecosand-fly ash mixture. Further experiments on shielding effectiveness measurement of cement mortar composite, incorporating ecosand-fly ash mixture can provide effective conclusions on the microwave attenuation characteristics, and its subsequent utilization for EMI tolerant constructions.

Abstract: In recent days deep-drawing is one of the most important methods used for sheet metal forming. The geometries of die/blank holder and punch are one of the parameters for deep-drawing. This paper presents an attempt to determine the effect of different geometries of die/blank holder, punch radii and blank holding force on deep drawing process for the formability of DP Steel of 1mm sheet. The numerical simulations are performed for deep drawing of cylindrical cups at a constant frictional coefficient of 0.12 and different blank holding forces of 10, 15 and 20kN are used. For numerical simulation PAM STAMP 2G a commercial FEM code in which Hollomon’s power law and Hills 1948 yield’s criterion is used. The die/blank holder profile used with an angles of α=0°, 12.5°, 15° and die/punch profile with a radii of R= 6 and 8mm were simulated to determine the influence of punch force and thickness distribution on the limit drawing ratio. The aim of this study is to investigate the effect of tool geometries on drawability of the deep-drawing process.