Development and strengthening of aluminium alloy (Al-Cu) by mechanical working and heat treatment

Understanding the mechanical properties of materials is one of the most difficult tasks faced by the solid state physicist and progress in this direction has not been as great as in the case of the electrical, thermal and magnetic properties. For the purpose of discussion it is convenient to classify the mechanical properties as elastic or plastic and as structure sensitive or structure insensitive. Elastic properties are the appropriate elastic constants, while plastic properties include the strength properties and the creep, fatigue and fracture characteristics. Modern cutting tools, gadgets, aerospace parts made from hard alloys have caused a real revolution in this field and they depend on the above properties. The finished parts are produced without machining and for an example, in the manufacture of gears by P/M, the technological process consists of simple and labour saving operations, obtaining the powder pressing, sintering and sizing. Based on the above fact the project is undertaken and keen interest is shown on the development and strengthening of aluminium alloy (Al- Cu Composites) by mechanical working and heat treatment

Analysis of properties of Al-Cu composition using P/M route

Aluminium is chemically active metal that owes its stability and corrosion resistance to an ever present protective film of oxide. It is well known that Cu-Al2O3 composite materials have high potential for use in structural applications in which enhanced mechanical characteristics are required. There fore ,oxidized copper is mixed with aluminium powder in a pot mill  and sintered at elevated temperature of 550 0 C. Copper composite with varying amount of 9%,11%,13% by weight of alumina was used to fabricate compact using powder metallurgy route. The blended powder was compacted at optimized load to produce compact of h/d ratio in range of 1.0 / 1.1 and then sintered at a temperature of 550 0 C for 1 1/2 Hours. Green density, sintered density, mechanical properties like hardness, compression test are estimated. The investigation shows that Al and Al matrix composites offer lower density, improved strength and stiffness and wear resistance. The compacts are extruded for further investigation

Influence of fluidity and Hausner’s ratio in the process behaviour of P/M of Al -% wt Cu Composite

The term ‘P/M’ covers the art of producing objects from metal powders or without adding any non metallicconstituents and without completely melting material. In order to produce engineering material one shouldstudy the flow of the powder. Because the powders may be pressed to the desired form in a suitable die andsubsequently heated to produce a welded alloyed or coalesced mass. The wide spread use of powders in theP/M industry has generated a variety of methods for characterizing the powder flow. Hence this paperdescribes the role of flow rate and fluidity of the powder composition which is taken for the investigationpurpose. The study helps the material may then be suitable for immediate use or may be further worked byconventional methods. Because the strength of finished engineering product depends on the flow rate of thepowder. Moreover the fluidity offers best article production with unique properties which is not obtained byother methods. The best example is bearings and filters with controlled porosity. For investigation purposevarious compositions of Al-Cu powder is used. With small variation the result is obtained. It is understoodthat the composition of Al –Cu is neither pyrophoric nor toxic in nature

IN VITRO STUDY OF ANTIMICROBIAL AND ANTIOXIDANT ACTIVITIES OF OXALIC ACID-DERIVED BIOACTIVE CHELATING AGENT

Objective: The aim of this study is to evaluate the biological potentials of sodium cadmium oxalate dihydrate complex prepared by a single diffusion method in the silica gel medium. Methods: The present complex was derived by the oxalic acid using a single diffusion method in gel medium and tested for single-crystal X-ray diffraction, ultraviolet-visible (UV) spectrum (190–500 mm), and solubility (distilled water at 20–29°C) studies. Antioxidant activity was determined by 2, 2-diphenyl-1-picrylhydrazyl assay, and antimicrobial activity was measured by agar well diffusion method. Results: The present chelating complex was successfully synthesized by gel technique. The solubility of sodium cadmium oxalate dihydrate was moderately good for deionized warm water. The UV spectral studies confirmed the chelating O-H, Na-O, and C-O bonds of the newly synthesized complex for the optical and biological properties. Conclusions: The metal-oxygen and oxygen-hydrogen bonds of the present newly synthesized sample much improved its optical, antimicrobial, and antioxidant activities and find its applications in the field of pharmaceutical and biomedical applications

SYNTHESIS AND CHARACTERIZATION IN VITRO ANTIMICROBIAL AND CYTOTOXICITY TESTING OF OXALIC ACID-DERIVED CADMIUM CHELATING AGENTS

Objective: The aim of this study is to investigate the growth, structure, spectral, solubility and biological activity of sodium cadmium oxalate dehydrate (NaCdOx) and cadmium oxalate trihydrate (CdOx) crystals prepared by a single diffusion method in the silica gel medium.Methods: The present crystals were grown using single diffusion methods and tested for XRD, UV absorption (190 to 1100 mm) and solubility (distilled water at 20-29 °C) studies. The antimicrobial efficacy of the grown samples at various concentrations (25, 50, 75 and 100 μg/ml) was studied against Streptococcus, (G+Ve), Pseudomonas aeruginosa (G-Ve) and Candida albicans (antifungal). The cytotoxicity evolution was carried out against human cervical cancer cell line (HeLa) using MTT assays.Results: The existing single crystals were successfully grown by silica gel technique. The solubility of sodium cadmium oxalate dehydrate (NaCdOx) was moderately good in deionized warm water. The FTIR spectral studies confirmed the chelating bands of the present samples and UV spectra showed the better the optical conductivity of as-grown crystals. The complexes showed good antimicrobial activity against all tested microbial strains and they exhibited a decrease in cytotoxicity activity.Conclusion: The gel method was suitable to grow metal complexes of legend crystals. The modification of structural properties of cadmium oxalate trihydrate (CdOx) by sodium doping was much improved the solubility, anticancer, antimicrobial activity and polarization by the high optical conductivity of sodium cadmium oxalate dehydrate (NaCdOx) compound. Hence sodium cadmium oxalate dehydrate (NaCdOx) might be a candidate for biomedical applications.Â

Cluster radioactivity in superheavy nuclei 299-306122

Cluster radioactivity is an intermediate between alpha decay and spontaneous fission. It is also an exotic decay obtained in superheavy nuclei. When a cluster decay is detected in superheavy nuclei, the daughter nuclei is having near or equal to doubly magic nuclei. We have investigated cluster decay of isotopes of He, Li, Be, Ne, N, Mg, Si, P, S, Cl, Ar and Ca in the superhaevy nuclei region 299-306122. We have also compared the logarithmic half-lives of cluster decay with that of other models such as Univ [1], NRDX [2], UDL [3] and Horoi [4]. From this study it is concluded that  cluster decay of 4He, 22Ne, 26Mg, 28Si 30Si, 34S, 40Ca and 46Ca are having shorter logarithmic half-lives compared to exotic cluster decay modes

Systematics of proton decay of actinides

255-262The phenomenon of proton emission from nuclear ground states limits the possibilities of the creation of more exotic proton rich nuclei that are usually produced by fusion-evaporation nuclear reactions. In the energy domain of radioactivity, proton can be considered as a point charge having highest probability of being present in the parent nucleus. Conclaves et al.1 studied the two-proton radioactivity of nuclei of mass number Aet al.2 reviewed the theories of proton emission to analyse the properties of nuclear matter. Maglione et al.3 analysed the proton emission from the some deformed nuclei. We have studied proton decay in almost all actinide nuclei. We have calculated the energy released during the proton decay (QP), penetration factor (P), and half-lives of proton decay. Proton decay half-lives are also longer than that of other decay modes such as alpha decay and spontaneous fission. To check the Geiger-Nuttal law for proton decay in actinide nuclei, we have plotted the logarithmic proton decay half-lives versus 1/sqrt(Q). The competition of proton decay with different decay modes such as alpha decay and spontaneous fission are also studied. We have also highlighted possible proton emitters with the corresponding energies and half-lives in the actinide region

Specific absorbed fraction of energy of silicon-boron alloys

213-217We have studied the energy absorption buildup factors and specific absorbed fraction of energy for the silicon-boron alloys of different composition such as alloy A-Si0.95-B0.05, alloy B- Si0.9-B0.1, alloy C- Si0.8-B0.2, alloy D- Si0.7-B0.3, alloy E- Si0.6-B0.4 and alloy F- Si0.5-B0.5. for wide energy range (0.015–15 MeV) up to the penetration depth of 40 mfp using geometric progression fitting method. Buildup factors increase with the increase in the penetration depth. It has been found that the shielding parameters such as mass attenuation coefficient, effective atomic number and buildup factor values are larger for the silicon-boron alloy Si0.95-B0.05 than the other studied silicon-boron alloys. Specific absorbed fraction of energy is maximum for the silicon-boron alloy Si0.95-B0.05. Hence, we can conclude that the silicon-boron alloy Si0.95-B0.05 is a good absorber of X-rays, gamma and neutrons among the studied alloys. The present study is useful in the field of radiation shielding

Cluster radioactivity in superheavy nuclei 299-302120

The cluster radioactivity is an unusual decay process observed in superheavy nuclei. When a cluster nuclei are emitted, the residual or daughter nuclei is having doubly magic nuclei or it may be neighbourhood of the same. We have studied cluster radioactivity [4He, 6Li, 9Be, 20,22Ne, 23N, 24-26Mg, 28-30Si, 31P, 32-34S, 35Cl, 36,38,40Ar, 40-46Ca ] in the superheavy nuclei 299-302120 using the nuclear and proximity model. The calculated cluster decay half-lives are compared with that of the other theoretical models such as Univ1, NRDX2, UDL3 and Horoi4. From the comparison of different models we have observed that the cluster nuclei with 4He, 9Be, 22Ne, 26Mg, 30Si, 34S, 40Ca and 46Ca are having smaller logarithmic half-lives than the exotic cluster decay modes