Impact of the gamma and neutron attenuation behaviors on the functionally graded composite materials

Gamma-ray and neutron shielding properties of the AA6082 + TiO2 (0-50wt.%) functionally graded composite materials (FGCMs) were investigated using the PSD software. The values of the mean free path (MFP), half-value layer (HVL), linear attenuation coefficients (LAC), mass attenuation coefficient (MAC), tenth-value layer (TVL), exposure buildup factors (EBF), effective atomic number (Zeff), effective conductivity (Ceff), and fast neutron removal cross-sections (FNRC) were found for the energy range between 0.015–15 MeV. The increase in the TiO2 content in the AA6082 composite material has raised the values of MAC and LAC. The calculations for the EBFs were carried out using the G-P fitting method for the energy range between 0.015–15 MeV and penetration depth of up to 40 mfp. The results revealed that HVL values ranged between 0.01-0.116 cm, TVL values ranged between 0.01-0.385 cm, FNRC values ranged between 7.918-10.017 cm-1, and Ceff values ranged between 5.67 x1010 and 9.85x1010 S/m. The AA6082 + TiO2 (50%) composite material was observed to provide the maximum photon and neutron shielding capacity since it offered the highest Zeff, MAC, and FNRC values, and the lowest HVL value. In terms of several aspects, the research is considered original. Besides contributing to several technologies including nanotechnology and space technologies, present research’s results may contribute to nuclear technology.

Enhancing the tensile strength of SiC reinforced aluminium- based functionally graded structure through the mixture design approach

PurposeThis article aims to study the tensile properties of a functionally graded composite structure with Al–18wt%Si alloy as the matrix material and silicon carbide (SiC) particles as the reinforcing element. More specifically, the study's primary objective is to optimize the composition of the material elements using a robust statistical approach.Design/methodology/approachIn this research, the composite material is fabricated using a combination of stir casting and the centrifugal casting technique. Moreover, the test specimen required to study the tensile strength are prepared according to the ASTM (American Society for Testing and Materials) standards. Eventually, optimal composition to maximize the tensile property of the material is determined using the mixture design approach.FindingsThe investigation results imply that the addition of the SiC plays a crucial role in increasing the tensile strength of the composite. The optical microstructural images of the composite show the adequate distribution of the reinforcing particles with the matrix. The proposed regression model shows better predictability of tensile strength. In addition, the methodology aids in optimizing the mixture component values to maximize the tensile strength of the produced functionally graded composite structure.Originality/valueLittle work has been reported so far where a hypereutectic Al–Si alloy is considered the matrix material to produce the composite structure. The article attempts to make a composite structure by using a combination of stir casting and centrifugal casting. Furthermore, it employs the mixture design to optimize the composition and predict the model of the study, which is one of a kind in the field of material science.

Dry wear behavior of A356-SiCp functionally graded composite in unidirectional and reciprocating contacts

Purpose The purpose of this study is to distinguish the difference in tribological behavior of functionally graded composites in two sliding modes, namely, unidirectional and reciprocating. Design/methodology/approach A356-(10 Wt.%)SiCp functionally graded composite material (FGM) was prepared by vertical centrifugal casting and then a comparison was made between the tribological characteristics using pin-on-disk and pin-on-reciprocating plate configurations under identical operating conditions (sliding distance (s): 350 m; load (W): 30 = W = 120 N, in steps of 30 N; and velocity (v): 0.2 = v = 1.2 m/s, in steps of 0.2 m/s). Two types of test pins were considered, namely, a test pin taken from the outer zone of the FGM with maximum particle concentration and a test pin taken from the inner zone of the FGM in a matrix-rich region. Findings The study revealed that, for the test pin taken from the outer zone of the FGM in the low-velocity range (0.2–0.4 m/s), the reciprocating wear of the friction pair was dominant, while unidirectional wear was dominant in the velocity range of 0.6–0.8 m/s for the entire load range investigated. However, when the velocity was increased from 1.0 to 1.2 m/s, conflicting nature of dominancy in the wear characteristics of the friction pair was observed, depending on the loading condition. In addition, the inner zone FGM pin underwent seizure in the reciprocating mode, whereas this phenomenon was not seen in the unidirectional mode. Originality/value Differences in wear and friction characteristics of FGM friction pairs in two different sliding modes were investigated over a wide range of operating parameters.

A RADIATION SENSITIVE ADHESIVE SYSTEM FOR FUNCTIONALLY GRADED COMPOSITE JOINTS

Adhesively bonded composite joints can help reduce weight in structures and avoid material damage from fastener holes, but stress concentrations formed at the edges of the adhesive bond line are a main cause of failure. Stress concentrations within the adhesive can be reduced by lowering the stiffness at these edges and increasing the stiffness in the center of the joint. This may be achieved using a dual-cure adhesive system, where conventional curing is first used to bond a lap joint, after which high energy radiation is applied to the joint to induce additional crosslinking in specific regions. Anhydride-cured epoxy resins have been formulated to include a radiation sensitizer enabling the desired cure behavior. Tensile testing was performed on cured systems containing varying levels of radiation sensitizer in order to evaluate its effects on young’s modulus as a function of radiation dose.