Gurmel Singh

Gamma radiation shielding analysis of lead-flyash concretes

Six samples of lead-flyash concrete were prepared with lead as an admixture and by varying flyash content - 0%, 20%, 30%, 40%, 50% and 60% (by weight) by replacing cement and keeping constant w/c ratio. Different gamma radiation interaction parameters used for radiation shielding design were computed theoretically and measured experimentally at 662keV, 1173keV and 1332keV gamma radiation energy using narrow transmission geometry. The obtained results were compared with ordinary-flyash concretes. The radiation exposure rate of gamma radiation sources used was determined with and without lead-flyash concretes.

Role of Different Range of Particle Size on Wear Characteristics of Al–Rutile Composites

The present article describes in detail the wear behavior of rutile-reinforced LM13 alloy composite at elevated temperatures. Rutile particles in different amounts were reinforced into LM13 alloy by the stir casting route. The microhardness measured at different areas indicates good interfacial bonding. Wear tests were conducted for composites containing rutile particles in 10 wt.% and 15 wt.% with variation in particle size (50–75 µm and 106–125 µm). The presence of ceramic particle in the matrix improves the hardness, wear resistance, thermal stability, and durability of the materials. The wear of composite at 200°C presented entirely different wear behavior mode than that at 250°C. The wear rate of fine size reinforced composite was substantially lower than that of coarse size reinforced composite with higher load at 200°C. A transition from mild-to-severe wear in composite was observed with higher load above 150°C. The morphology of wear track and debris indicates that nucleation of cracks around the void on the interface of the particles is the main cause of surface damage.

Effect of Particle Size on Wear Behavior of Al–Garnet Composites

Metal matrix composites are the potential candidate for the variety of structural applications such as those in aerospace, transportation, and defense because of the wide range of mechanical properties they possess. The present study aims to analyze the effect of particle size on the microstructural features, microhardness and wear behavior of composites. Composites reinforced with garnet particles of different size range (fine 50–75 µm) and (coarse 106–125 µm) in Al–Si alloy (LM13) were prepared by stir casting route. The microstructure obtained reveals nearly uniform distribution of ceramic particles inside the LM13 alloy matrix. Reinforcement of fine size particles has led to the increase in hardness of fine size reinforced composite to nearly 9% over coarse size reinforced composites, whereas wear resistance improved by 7% and 5% for 10 and 15 wt% reinforcement, respectively. However, the wear resistance increased considerably up to 13% for fine size reinforced composite when the reinforcement content was increased from 10 to 15 wt%.

Influence of particle size and temperature on the wear properties of rutile-reinforced aluminium metal matrix composite

In the present investigations, LM13 aluminium alloy reinforced with 15 and 20wt.% rutile mineral of fine (50–75 µm) and coarse (106–125 µm) size range was prepared through stir casting technique. The microhardness on different phase of the composite was measured to check the interfacial bonding of particles with the base material. The wear properties of the samples were studied using pin-on-disc tribometer at high load (49 N) with variation in temperatures from 50℃ to 300℃. Wear results indicated that the composites containing fine size reinforced particles showed around two times higher wear resistance over a wide range of temperature than the composite-containing coarse particles. A transition in wear mode from mild to severe was observed above 200℃. Wear track and wear debris were analysed to understand the nature of wear.

Effect of Flyash Addition on Mechanical and Gamma Radiation Shielding Properties of Concrete

Six concrete mixtures were prepared with 0%, 20%, 30%, 40%, 50%, and 60% of flyash replacing the cement content and having constant water to cement ratio. The testing specimens were casted and their mechanical parameters were tested experimentally in accordance with the Indian standards. Results of mechanical parameters show their improvement with age of the specimens and results of radiation parameters show no significant effect of flyash substitution on mass attenuation coefficient.

Wear performance of garnet aluminium composites at high contact pressure

To satisfy the needs of the engineering sector, researchers and material scientists in this area adopted the development of composites with tailor made properties to enhance efficiency and cost savings in the manufacturing sector. The technology of the mineral industry is shaping the supply and demand of minerals derived materials. The composites are best classified as high performance materials have high strength-to-weight ratios, and require controlled manufacturing environments for optimum performance. Natural mineral garnet was used as the reinforcement of composite because of satisfactory mechanical properties as well as an attractive ecological alternative to others ceramics. For this purpose, samples have been prepared with different sizesof the garnet reinforcement using the mechanical stirring method to achieve the homogeneously dispersed strengthening phase. A systematic study of the effect of high contact pressure on the sliding wear behaviour of garnet reinforced LM13 alloy composites is prese...

Compressive strength of the mineral reinforced aluminium alloy composite

This paper presents the results of quasi-static compressive strength of aluminium alloy reinforced with different concentration of rutile mineral particles. The reinforced material shows increase in compressive strength with 5wt% rutile concentration as compared to the base alloy. This increase in compressive strength of composite is attributed to direct strengthening due to transfer of load from lower stiffness matrix (LM13 alloy) to higher stiffness reinforcement (rutile particles). Indirect strengthening mechanisms like increase in dislocation density at the matrix-reinforcement interface, grain size refinement of the matrix and dispersion strengthening are also the contributing factors. The decrease in compressive strength of composite with the increased concentration of rutile concentration beyond 5 wt.% can be attributed to the increase in dislocation density due to the void formation at the matrix-reinforcement interface.