Shashi Prakash Dwivedi

A comparative study of waste eggshells, CaCO3, and SiC-reinforced AA2014 green metal matrix composites:

The influences of weight percentage of different reinforcement particles such as SiC particles, waste uncarbonized eggshell particles, carbonized eggshell particles, and CaCO3 powder were compared in the processing of aluminium-based metal matrix composite. The results revealed that by the addition of SiC particles up to 10 wt.% and waste eggshell particles up to 12.5 wt.% in AA2014 matrix alloy, the tensile strength, hardness, and fatigue strength increased. Toughness and ductility decreased by the addition of SiC and eggshell particles in AA2014 matrix alloy. Corrosion rate decreased by the addition of SiC particle up to 7.5 wt.% and eggshell particles up to 12.5 wt.%. Results showed that hardness and heat-treatable properties are improved after the addition of SiC reinforcement particles in AA2014 aluminium alloy as compared to eggshell particles. However, porosity and overall cost increased after addition of SiC particles in AA2014 alloy. Corrosion rate increased after the heat treatment for all reinforced metal matrix composite. These results showed that using the carbonized eggshell as reinforcement in the AA2014 alloy gave better physical properties at lower cost as compared to SiC particles. Proper wettability was observed between matrix and reinforcement material for both carbonized eggshell particles and SiC particles. No wettability was observed between AA2014 alloy and CaCO3 reinforcement particles. Poor wettability reduced the mechanical properties of AA2014/CaCO3 metal matrix composite.

RETRACTED: Mechanical and metallurgical characterizations of AA2014/eggshells/SiC hybrid green metal matrix composite produced at optimum reinforcement parameters:

AA2014/carbonized eggshells/SiC hybrid green metal matrix composites are fabricated by electromagnetic stir casting process at optimum parameters (squeeze pressure of 60 MPa, stirring current of 12 A, stirring time of 180 s and matrix pouring temperature of 700 C, respectively). In the range of reinforcement parameters, the result shows that the tensile strength of hybrid metal matrix composite increases with the increase in carbonized eggshell and SiC preheat temperature. Whereas the tensile strength of AA2014/carbonized eggshell/SiC hybrid green metal matrix composite decreases with the addition of SiC beyond 2.5 wt%. The tensile strength of AA2014/carbonized eggshell/SiC hybrid green metal matrix composite increases with the increase in the eggshell weight percent until it reaches the center value (7.5 wt%); the tensile strength then starts to decrease with the increase in eggshell weight percent beyond the center limit (7.5 wt%). The optimum values of weight percent of carbonized eggshell, preheat temperature of carbonized eggshell, preheat temperature of SiC and SiC weight percent were found to be 7.5%, 300 C, 500 C and 2.5%, respectively, to get the maximum tensile strength (predicted: 259.12 MPa). The results reveal that sample of AA2014/7.5% eggshell/ 2.5% SiC shows best result among all the selected samples. The microstructure presents that the reinforcements (7.5 wt% carbonized eggshell and 2.5 wt% SiC particles) are uniformly distributed in the matrix AA2014 alloy. Transmission electron microscopy image shows proper wettability between AA2014 alloy and reinforcements (7.5 wt% carbonized eggshell and 2.5 wt% SiC particles). Density, X-ray diffraction, cost estimation, hardness, toughness, ductility and fatigue strength were also calculated to see the effect of carbonized eggshell and SiC addition in matrix alloy AA2014.

Effects of waste eggshells and SiC addition on specific strength and thermal expansion of hybrid green metal matrix composite

Chicken eggshell waste is an industrial byproduct, and its disposal constitutes a serious environmental hazard. Chicken eggshell can be used in commercial products to produce new materials with low cost and density. Low density material which can sustain at higher temperature is a remarkable area of research. Keeping these facts in the mind, the present investigation aims to study the physical behaviour, specific strength and thermal expansion of AA2014/SiC/carbonized eggshell hybrid green metal matrix composites. Microstructure of hybrid green metal matrix shows that the reinforcement particles (SiC particulates and carbonized eggshells particles) are uniformly distributed in the matrix AA2014 alloy. Specific strength for the composites containing 2.5wt.% SiC and up to 7.5wt.% carbonized eggshell was observed to be higher than that of the other selected composites. While for the same composition (AA2014/2.5% SiC/7.5% carbonized eggshell composites), porosity was observed lower than other selected composites. The results revealed that sample of AA2014/2.5% SiC/7.5% carbonized eggshell showed minimum cross sectional area reduction after the thermal expansion at 450°C among all the selected samples. Overall costs of hybrid metal matrix composites were also calculated.

Synthesis and mechanical behaviour of green metal matrix composites using waste eggshells as reinforcement material

Abstract Chicken eggshell (ES) is an aviculture by-product that has been listed worldwide as one of the worst environmental problems. The effective utilisation of ES biowaste is strongly encouraged in our society due to environmental and economic reasons. The aluminium alloy (AA) 2014/5 wt% carbonised ES metal matrix composite used in this study was fabricated by electromagnetic stir casting technique at parameters of 12 A (current), 180 s (time) and 700°C (matrix pouring temperature), respectively, and immediately extruded on universal testing machine at 60 MPa using cylindrical H13 tool steel die coated with graphite to avoid upper flow of ES particles and to improve wettability of carbonised ES with AA2014 alloy. Microstructures of composites show uniform distribution of carbonised ES particles. Density and overall cost of the metal matrix composite decreases 3.57% and 5%, respectively, when carbonised ES particulate is added 5% by weight. Tensile strength, hardness, toughness and fatigue strength of AA2014/5 wt% carbonized eggshell composite were also measured. Results show an improvement in these mechanical properties with addition of ES in the matrix alloy.

Effects of waste eggshells and SiC addition in the synthesis of aluminum hybrid green metal matrix composite

Abstract The mechanical behavior, physical behavior, microstructural characteristics, and corrosion behavior of AA2014/silicon carbide (SiC)/carbonized eggshell hybrid green metal matrix composites (MMCs) were investigated. Twenty-five samples of hybrid composite with different combinations of SiC and carbonized eggshell particles in AA2014 matrix alloy were prepared. Microstructure presents that the reinforcement particles (SiC and eggshells) are uniformly distributed in the matrix AA2014 alloy. Transmission electron microscope image shows proper wettability between SiC, carbonized eggshell, and AA2014 aluminum alloy. The tensile strength and the fatigue strength for the composites containing 2.5 wt.% SiC up to 7.5 wt.% carbonized eggshell were observed to be higher than that of the other selected composites. The hardness values for the composites containing 12.5 wt.% SiC and 2.5 wt.% carbonized eggshell were in all cases higher than that of the other composites. The results show that toughness decreases with the increase in the weight ratio of SiC and carbonized eggshell in the composites. The results reveal that the sample of AA2014/2.5% SiC/12.5% carbonized eggshell shows minimum corrosion rate among all the selected samples. Density, porosity, and overall cost of hybrid metal matrix composites were also calculated to see the effects of carbonized eggshell and SiC addition in AA2014 matrix alloy.

Optimization of Laser Transmission Joining Process Parameters on Joint Strength of PET and 316 L Stainless Steel Joint Using Response Surface Methodology

The objective of the present work is to study the effects of laser power, joining speed, and stand-off distance on the joint strength of PET and 316 L stainless steel joint. The process parameters were optimized using response methodology for achieving good joint strength. The central composite design (CCD) has been utilized to plan the experiments and response surface methodology (RSM) is employed to develop mathematical model between laser transmission joining parameters and desired response (joint strength). From the ANOVA (analysis of variance), it was concluded that laser power is contributing more and it is followed by joining speed and stand-off distance. In the range of process parameters, the result shows that laser power increases and joint strength increases. Whereas joining speed increases, joint strength increases. The joint strength increases with the increase of the stand-off distance until it reaches the center value; the joint strength then starts to decrease with the increase of stand-off distance beyond the center limit. Optimum values of laser power, joining speed, and stand-off distance were found to be 18 watt, 100 mm/min, and 2 mm to get the maximum joint strength (predicted: 88.48 MPa). There was approximately 3.37% error in the experimental and modeled results of joint strength.

Comparison of Microstructure and Mechanical Properties of A356/SiC Metal Matrix Composites Produced by Two Different Melting Routes

A356/SiC metal matrix composites with different weight percent of SiC particles were fabricated by two different techniques such as mechanical stir casting and electromagnetic stir casting. The results of macrostructure, microstructure, and XRD study revealed uniform distribution, grain refinement, and low porosity in electromagnetic stir casing samples. The mechanical results showed that the addition of SiC particles led to the improvement in tensile strength, hardness, toughness, and fatigue life. It indicates that type of fabrication process and percentage of reinforcement are the effective factors influencing the mechanical properties. It is observed that when percentage of reinforcement increases in electromagnetic stir casting, best mechanical properties are obtained.

Friction and Adhesive Wear Study of HVOF Sprayed Ni–WC–Co-Based Powder Coating

Ni-based alloys are being widely used to improve the wear resistance of various industrial components in normal and severe environments and addition of rare earth elements to these alloys further improves the various mechanical and tribological properties of the coatings. In the present work, commercially available MEC 86 (NiCrBSi/WC–Co = 65/35) powder was modified with the optimum addition of 0.4 wt.% La2O3. The coatings were deposited by high velocity oxy-fuel (HVOF) spraying process. Rare earth addition refines the microstructure and increases the microhardness of the coatings. The increase in microhardness with the addition of La2O3 is approximately 22%. Sliding wear resistance of the coating modified with La2O3 is higher than of that without La2O3. The average wear resistance increases by approximately 14%. Further, the addition of La2O3 to the coating reduces the friction coefficient as compared to the one without the rare earth element. The coefficient of friction was found lower with the addition of La2O3, which is approximately 18%.

Influence of precipitation hardening parameters on the microstructure and mechanical properties of extruded AA2014/eggshells green composites

The AA2014/5 wt. % carbonized eggshells metal matrix composite used in this study was fabricated by electromagnetic stir casting technique and immediately extruded on universal testing machine at 60 MPa using cylindrical H13 tool steel die coated with graphite to avoid upper flow of eggshells particles and to improve wettability of eggshells with AA2014 alloy. Microstructures of composites show some agglomerations in non-extruded samples while uniform distribution of carbonized eggshell particles. Optimum combination of precipitation hardening parameters achieved using response surface methodology to further improve the properties of AA2014/5 wt. % eggshell composites. Optimum values of solutionizing time, aging temperature and aging time were found to be 4.5 h, 250℃ and 13.5 h, respectively. More grain refinement of extruded AA2014/5 wt. % eggshell composites were observed after heat treatment at optimum precipitation hardening parameters. After heat treatment, fractographs of the AA2014/5 wt. % eggshells composite showed that fracture is dominated by trans-granular type. Density of the AA2014 is 5% higher than AA2014/5 wt. % eggshells metal matrix composite. It is observed that mechanical properties improve when carbonized eggshell particles are reinforced in matrix AA2014 aluminium alloy. After the heat treatment at optimum precipitation hardening parameters, mechanical properties are further improved.