Search

Aluminium metal foams offer low density (∼10–15% of bulk material) possessing cellular structure that ensures unique features with high stiffens, better energy absorption, thermal and acoustic properties. Selection of different foaming agents for preparing AA6061 foam samples are indeed an industrial relevance for better control over porosity and its dimensions, strengths (tensile, flexural and compression) useful for distinguished applications. Three foaming agents such as wax powder, magnesium hydroxide, and titanium hydride are selected with varying 3–9 weight percentage to prepare metal foams viz. powder metallurgy technique. For the prepared foam samples the percentage porosity, pore dimensions (maximum pore size, and equivalent diameter) and strengths were examined. Wax powder foaming agent resulted with a maximum strength in foam samples compared to magnesium hydroxide and titanium hydride. Scanning electron microscope with energy dispersive spectroscopy analysis revealed that there is no evidence of foreign elements and confirm uniform distribution of porosity in the foam samples. [ABSTRACT FROM AUTHOR]

The consumption of fossil fuels is continuously increasing due to large number of automobiles and high demand for energy. Fossil fuels will not only become extinct in near future, but also pollute the environment. The present research work is focused on finding an eco-friendly alternate energy source through the production of bio-diesel. Naturally available low-cost Garcinia Gummi-Gutta seed was used to produce the biodiesel employing the transesterification process widely utilised in industries. The maximum biodiesel yield was primarily dependent on the optimisation of transesterification parameters (reaction time, percent of methanol and sodium hydroxide). Response Surface Methodologies (RSM) such as Box-Behnken design (BBD) and Central composite design (CCD) were used to conduct the experiments and analyse the transesterification parameters relationship with biodiesel yield. Results showed that, the methanol contribution was more as compared to sodium hydroxide and reaction time towards the yield of the biodiesel. The mathematical regression equations developed, related to biodiesel yield and transesterification parameters by utilising both the CCD and BBD models. The performance of BBD was found to be slightly better than that of CCD in making prediction of the biodiesel yield. Experimentally, the Teaching Learning-based Optimisation (TLBO) determined optimal transesterification parameters resulting to 96.2% biodiesel yield. [ABSTRACT FROM AUTHOR]

The current research focuses on developing an Aluminium/Gr-CNT hybrid composite with two nanoscale reinforcements (Graphene and CNT). Stir casting was used to create hybrid composites with different weight fractions of graphene (1, 2, 3, and 5 Wt. %.) and a fixed CNT content of 2 Wt.%. The influence of varying graphene content with fixed CNT content on density, microstructure, hardness, and wear on hybrid MMC's was investigated. Hardness and wear tests were carried out as per ASTM E384 and G99 standards. Microstructure showed a relatively uniform dispersal of reinforcements (Gr and CNT) in pure Al matrix. The study revealed that the hardness of Al/Gr/CNT hybrid composites is higher than that of pure aluminium. The increase in hardness and addition of reinforcements lead to a significant reduction in wear rate. Wear surface morphology studies reported that pure aluminium had undergone an adhesion wear mechanism, whereas Al/Gr/CNT hybrid composites had undergone abrasion wear. [ABSTRACT FROM AUTHOR]

Metal matrix composites (MMCs) processed with significant technological interventions offer excellent properties at reduced cost resulted in a wide range of engineering applications. In MMCs, ensuring homogeneous dispersal of reinforcement in metal matrix to obtain aggregate properties in composites still remains as a challenging task. Industrial waste-based fly ash (FA) particles were used as a reinforcement material to fabricate Al 6113 composites. Ultrasonic- assisted stir casting technique was employed to prepare composites. FA particles with different weight proportions (3, 6 and 9 wt.%) are reinforced to prepare the composites and examine their properties (micro-hardness, compressive strength and wear rate). Furthermore, properties are also examined for the prepared as-cast composites subjected to heat treatment conditions. Microstructural analysis confirms, 6% FA particles are fairly and evenly distributed in Al6113 matrix material resulted in best properties. Al6113 with 6% fly ash particles improves 8.68% hardness and 61.6% compression strength of the compared to as-cast Al6113 specimen. Heat-treated composites showed a significant improvement from 73.7 to 82.5 HV for hardness, 75.61 to 130.7 MPa for compression strength, and decreased values in wear rate from 0.9233 to 0.4298 mm3/min, and Coefficient of Friction (CoF) from 0.648 to 0.319 compared to as-cast Al 6113 specimens. [ABSTRACT FROM AUTHOR]

The microstructure and mechanical attributes of the friction stir welded aluminium metal matrix composites (AMCs) are reported in this paper. Impacts of friction stir welding (FSW) process variables on the mechanical properties are evaluated. Metallographic studies showed that variation in welding process variables' plays a vital role in obtaining recrystallised equiaxed fine-grain structures. The formed joint region indicates a gradual reduction in grain size as it moves from top to bottom of the weld region due to variation in the heat generation. Process variables like tool movement along the joint direction and tool revolution speed govern the joint strength of AMCs. Beyond the optimum values of process variables, the weld quality and joint strength of the welded part deteriorate due to the inappropriate stirring of the material at the weld region. The highest joint strength obtained for tool movement along the direction was 80 mm/min, and the revolution of the tool was 1000 rpm. [ABSTRACT FROM AUTHOR]

The present research work is focussed on establishing the complex nonlinear input–output relations of a furan resin-based molding sand system. Further, a set of input parameters, which will result in optimized mold properties, is determined. Grain fineness number, setting time, percentage of resin, and hardener are considered as process variables. Mold properties, such as green compression strength, shear strength, mold hardness, gas evolution, permeability, and collapsibility are treated as the process outputs. Nonlinear input–output relations have been developed and statistical analysis has been carried out by utilizing design of experiments, central composite design. Surface plots are developed to study and analyze the input–output relations. The input parameters that will result in best molding conditions and improve casting quality characteristics are determined by utilizing desirability function approach and multiple particle swarm optimization-based crowding distance (MOPSO-CD) techniques. The optimum value for the process variables namely grain fineness number, furan resin, hardener, and setting time are found to be equal to 55, 1.85, 1.2, and 60, respectively. The quality characteristics of the castings namely yield strength, ultimate tensile strength, hardness, density, and secondary dendrite arm spacing are found to improve by 14.03%, 15.08%, 14.14%, 12%, 2.22%, and 12.24%, respectively for the castings made in optimized molding sand conditions. [ABSTRACT FROM AUTHOR]