Papers by Keyword: Hardness Test

Abstract: L-asparagine and potassium chloride were used in a 2:1 ratio for the production of L-asparagine-based crystals such as L-asparagine admixture with potassium chloride (LAPC) utilizing deionized water as the solvent. The same process was used to synthesize L-asparagine admixtured with Glycine (LAG). To grow these crystals, the synthesized salts of its were used. The samples' saturated solutions were made separately, stirred vigorously for two hours, and then filtered separately. The solutions went through a slow evaporation process. Powder XRD studies reveals the various peaks present in the crystals. FTIR analysis provides the numerous functional groups connected to the produced crystals. The generated crystals are transmittable, according to studies of the UV-VIS spectrum. The mechanical behavior such the crystals belong to hard or soft category was also discussed.

Abstract: There is a significant improvement in specific strength and wear resistance of metal matrix composites (MMCs) in comparison to unreinforced alloys. Low-density reinforcements such as SiC havethe advantageof beingrelatively inexpensive and readily available abundantly and is cost-effective among the several uneven dispersoids used. Meagre work is carried out on processing of Al2219-SiC MMCs which is the originality of current work. The Al2219 matrix alloy in the current study was reinforced with different weight percentages of SiC (3%, 5%, and 7%), and it was produced by the stir casting process. Its microstructure and physical properties were examined, and it was then compared to the alloy as-cast. A study of SiC reinforced Al2219 MMC characterization and stir casting technology is presented in this paper to illustrate its salient features.

Abstract: Aluminum (Al) - Silicon Carbide (SiC) metal matrix composite is one of the widely used composites in today’s manufacturing industry. Al-SiC composites are produced through several methods such as casting and powder metallurgy, but its production through Reverse Two-Step Sintering (R-TSS) process in powder metallurgy has not been addressed so far. The present work focuses on manufacturing Al-SiC metal matrix composite through reverse two-step sintering process in powder metallurgy. The reinforcement element SiC is embedded with metal matrix element Al in different proportions. Then the consolidated mixture is compacted using the die and punch setup followed by a two-step sintering process suggested by Wong; thereby, the final compact is produced. Further, the processed sample is analyzed for density and hardness tests.

Abstract: The Aluminum alloys and its composites are used in the aerospace, automobile and marine industries due to their higher strength, stiffness and wear resistance properties. This study is focused on mechanical and tribological study of Al 7075 hybrid composite reinforced with B₄C, Gr and Fly ash. The reinforcements are added to Al alloy in three different compositions such as (4wt% B₄C/4wt% Gr/7wt% Fly ash, 4wt% B₄C/5wt% Gr/8wt% Fly ash and 4wt% B₄C/6wt% Gr/9wt% Fly ash). The stir casting machine was used for manufacturing hybrid composites. Hardness and wear tests were conducted for three different Al 7075 hybrid composites. The microstructure showed that the reinforcement was uniformly distributed in the matrix without agglomeration. The hardness and wear test results revealed that the composite with 4wt% B₄C /6wt% Gr/9wt% Fly ash exhibited an increase in hardness value of about 22.69% and the minimum wear rate as compared to other composites.

Abstract: The goal of this study was to characterize the mechanical behavior of dentin, dental enamel and a nanoparticulate composite resin, used in dental restorations. This characterization was performed through the static and dynamic Vickers hardness test. As for the biological tissue assays, third included human molars were used. The nanoparticulate resinous composite was condensed into a matrix, measuring approximately 10x10x2mm. The obtained HV values were represented by hardness maps. The distribution of hardness values along the enamel and dentin structures occurred unevenly in the two hardness analyzes. For dental enamel, there were differences in hardness values when compared dynamic to static tests. This difference did not occur in dentin. It was observed that the mechanical behavior of the resinous composite resembled more the behavior of the dentin than the enamel.

Abstract: Magnesium addition produce modification level of silicon’s eutectic for Al-Si-Mg. An increase in magnesium content will increase mechanical properties value of ADC 12 alloy. Highest hardness value reached when Mg content is over 4%. Properties of material’s increased because Mg that added to the alloy will bind with Si and form Mg₂Si compound. Where the Mg₂Si compound will close the empty space in crystal structure of Al-Si-Mg and the distance between the grain is getting closer so that ADC 12 alloy possess improved strength and hardness. ADC 12 alloy with the addition of 8% magnesium variation will have the highest hardness value, which is 143.44 BHN

Abstract: The process of continuous extrusion Conform, relating to modern energy-efficient metalworking technologies, is now widespread in the production of hollow and solid long-cut profiles of various cross-sections made of aluminum and copper alloys. However, in questions relating to the metal flow pattern and the formation of microstructure and mechanical properties, directly at the deformation zone, it has not studied sufficiently [1]. The work aimed at studying the nature of the metal flow and the transformation of the microstructure and mechanical properties of the copper alloy GOST-M1 (DIN-ECu-57) in the deformation zone during the pressing of round (Ø 8, 24, 30 mm) and flat (10 × 30, 10 × 60, 10 × 80, 10 × 100 mm) profiles. It was performed on the basis of New Metallurgical Technologies Ltd. and the department of metal forming of the NUST MISiS. In the pressing process, the templates of these profiles were selected, further samples for experiment were made and the study of the nature of the alloy flow in the longitudinal direction were carried out (continuous casting - deformation center - finished profile).

Abstract: Nickel based superalloy materials have being extensively used in aerospace and other high tech industries. In the present work, the effect of different substrates on the mechanical properties of the coating-substrate interface has been studied. To this end, alloy 718, commercially known as Inconel 718, was deposited on alloy 718 and low carbon steel substrates using High Velocity Oxygen Fuel (HVOF) technique at the same condition. The bonding strength of the interfaces evaluated using Vickers indentation test on the coating-substrate interface. Hardness results were subjected to a valid empirical method to estimate the fracture toughness. Results illustrated that using the same material as coating and the substrate led to stronger interface bonding strength due to higher hardness, fracture toughness, and less crack propagation.

Abstract: Due to the inhomogeneous mechanical properties of laser welding joints, it is necessary that the local mechanical properties of welding joints are measured for the assessment of the whole welding joints. Especially for mechanical properties test in heat affected zone of welding joints. Two methods of micro shear test and hardness test to measure mechanical properties of micro-zones were introduced. Using these two methods the mechanical properties of the micro-zones of X80 pipeline welding joint are determined and compared. The results showed that the micro shear test could be intuitively, quantitatively and continuously describe the strength and plasticity of the regional heterogeneity distribution, suitable for the assessment of the mechanical properties and fracture toughness of welding joints.

Abstract: This paper studies the mechanical properties of the aramid fiber reinforced epoxy resin composite by varying the percentage composition. Three different compositions of aramid fiber are 30 %, 35 % and 45 % by weight. The aramid epoxy composite was manufactured by the vacuum suction method. The manufactured composites are then cured by the hot air oven for 180 minutes. The prepared composites undergo through various tests such as the tensile test, hardness test and impact test. The results of the tests on the three compositions analyzed and variation in its mechanical properties is noted.