Solid State Phenomena Vol. 356

Abstract: The control of the residually stressed γ’-FCC phase in the grain boundaries that affects super-elasticity in the promising Fe-Mn-Al-Ni shape memory alloy (SMA) and grain size enhancement was an epitome for research in the current study. New composition Fe-33Mn-17Al-8.5Ni (at. %) was designed with the help of thermocalc software TCFE 11 database, produced in an electric arc furnace under an argon atmosphere and systematically investigated in the as-cast and heat-treated conditions. Characterization was performed using optical microscopy, X-ray diffraction measurements (XRD), and compression tests. Controlling the cooling conditions after heat treatment (HT) with high flowrate air cooling helped to reduce on the formation of the detrimental phase, γ’ at the grain boundaries as well as observed some grain growth in the microstructure without necessarily causing cracking as reported previously with quenching in cold water. The yield strength depicting the stress-induced martensitic transformation was 925 MPa for as cast and 909 MPa upon heat treatment. From cyclic compression loading/deloading training, a recovery strain of 2.1% and 2.3% was attained at 800 MPa maximum stress in the as-cast and heat treated-conditions, respectively.

Abstract: In this paper, a novel lightweight and low-cost Al₃₅Mg₂₀Zn₁₅Cu₁₀Si₂₀ at. % (Al_26.17Mg_13.47Zn_27.18Cu_17.61Si_15.57 wt.%) has been successfully designed, produced, and characterized. The thermophysical parameters were used to understand the phases associated with this alloy that show a low density of 3.42 g/cm³. The designed alloy was manufactured using both the arc and the muffle furnace. The alloy was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with an energy dispersive spectrometer (EDS). The alloy is characterized by a multiphase microstructure with three major phases including Mg₂Si intermetallic phase and eutectic. The volume fraction of the eutectic and the intermetallic phases are 37.83 and 34.99 respectively. The heat capacities of the alloy were also determined by means of differential scanning calorimetry (DSC). The alloy provides a high latent heat of up to 124 J/g, which is one of the highest among the high-temperature metallic materials. The present work provides valuable information for researchers wishing to design and manufacture industrial-grade high-entropy alloys (HEAs).

Abstract: The current paper focuses on enhancing the manufacturability of AZ61 magnesium alloys by heat treatment. Specimens are subjected to solution heat treatment. First, all samples underwent a 15-hour treatment at 415°C before aging at 50°C, 100oC, and 150°C. The specimens were furnace cooled and quenched after achieving the precise aging temperature. The results have been extracted from tensile and cupping tests. The outcomes of each test have been compared with the data taken without heat treatment, so the ductility increase can be observed. Tests revealed better results for furnace-cooled specimens. The increase in formability of about 9% along with a decrease in strength of only 11% is observed for 150°C aging temperature.

Abstract: Due to their numerous applications in the aerospace, chemical, and nuclear power industries, environmentally responsible superalloy machining is a major problem in the current production environment. Additionally, Ni-based superalloys are regarded as difficult to manufacture because of their great strength under hot and chemically reactive settings. Therefore, it is necessary to machine these materials using adequate cooling and lubricating solutions. Current study has been based on the optimisation and modelling of turning Hastelloy C-276 under dry, flood, and least lubrication system. A Taguchi L-9 arrangement was used as plan of experiment and modeling was enabled through ANOVA, regression analysis and Taguchi optimization. The results depicted optimal parameters for surface roughness and temperature at v₂-f₁-d₁-CE₃ and v₁-f₂-d₁-CE₃. Likewise, for CRC and shear angle the best combination was observed at v₃-f₃-d₂-CE₂. From ANOVA analysis, the benefaction of C.E, depth of cut and feed rate on S.R been listed as 46.70%, 40.44% and 10.66%. Likewise, for temperature cutting speed has benefaction of (53.09%), cooling environment (23.94%), depth of cut (6.10%) and feed rate 5.49% . In similar fashion, CRC and Shear angle were influenced by feed rate and cutting speed having contribution of 62.89% and 5.15% respectively. Furthermore, minimum standard error between the fitted and observed values for S.R., temperature, CRC, and shear angle were calculated as 0.0149, 7.66, 0.267, and 1.80 units. Finally, the marginal reduction of cutting temperature and surface roughness through utilization of MQL implies the sustainable machining conditions.

Abstract: ITER IF coils and the German WX-7 star simulator fusion reactor both use cyanate ester/epoxy resin as the matrix material for their insulation structure. The main reason is that cyanate ester/epoxy resin insulation materials have low-temperature mechanics and radiation resistance, and have extremely low rheological properties and long applicability periods. However, high-energy polymerization will occur when the two are mixed, releasing a huge amount of heat. This study used different molds to prepare cyanate ester/epoxy resin (mass ratio 4:6), and used DSC (Differential Calorimetry Scanning) thermal analyzer and temperature monitoring to study the curing behavior and thermal stability of cyanate ester-modified epoxy resin-based materials. After multiple optimizations, the resin was completely cured within a controllable range, and there was no significant change in the glass transition temperature before and after adjustment.

Abstract: Addition of high percentage of palm stearin (PS) into a blend with high density polyethylene (HDPE) may result in the blend instability and poor flowability of the composite during injection moulding process. The undesirable effect of the PS addition arises from lack of interaction between the PS and HDPE matrix. To improve the interaction between the two components, a compatibilizer was added to the blend. The objective of this work is to study the effect of glycerol monostearate (GMS) compatibilizer concentration (1-5 wt%) on the HDPE-PS composite with PS content of 40 wt.%. The thermal properties of the HDPE-PS composite were characterized using torque analysis, differential scanning calorimetry (DSC) analysis and rheology analysis. It was found that melting temperature of the HDPE-PS composite decreases with GMS concentration. The presence of GMS in the HDPE-PS composite had improved composite flowability indicate suitability of the GMS as compatibilizer for the HDPE-PS composite.

Abstract: Poly(ethylene carbonate) (PEC) is a form of aliphatic polycarbonate, a biodegradable polymer made via the copolymerization of carbon dioxide and epoxides. The poor thermal stability and mechanical properties of these aliphatic carbonates are attributed to the carbon structure's flexibility, which restricts their applications. By combining PEC with organoclay CP180, this study addressed the weaknesses of PEC with organoclay addition. A physical blending technique was employed to generate PEC/organoclay composites with a 10-50 wt.% ratio of organoclay. The blended material's thermal characteristics were analyzed using differential scanning calorimetry (DSC), and the mechanical characteristics were measured using a universal tensile machine. The Field Emission Scanning Electron Microscopy (FESEM) analysis determined the blends' morphology. Before the torque value for all curves grew with the addition of CP180 material to the PEC matrix, it became constant. It reached a high value due to the shear-thickening behavior of the PEC matrix with organoclay addition. T_g of PEC increased by more than 7°C by 40 wt.% organoclay addition, as evident in the hindrance of PEC flexibility, significantly increased the toughness of this PEC. From the FESEM images, the formation of large silicate starts to aggregate effectively, lowering the interfacial area between organoclay and PEC as the clay content continues to rise, as shown by 50 wt.% organoclay addition.

Abstract: In this study, various NR:EPDM:EVA rubber foams were prepared. The ratios of NR:EPDM:EVA were at 50:20:30 and 50:10:40. The amounts of blowing agent, dinitrosopentamethylenetetramine (or Supercell DP) were 5, 6, and 7 part per hundred of rubber (phr). The vulcanizing agent, dicumyl peroxide (or DCP) loadings were at 0.7 and 1 phr. The influence of rubber formula on the performance of the obtained rubber foam was discussed here. The results showed that increasing EVA proportion and Supercell DP loading and decreasing DCP loading led to the decrease in density, thus giving the lower thermal conductive rubber foam which was suitable for using as an insulating ceiling board. However, the above condition gave the rubber foam with slightly inferior mechanical properties including lower hardness and higher % compression set.

Abstract: Nickel-Phosphorous/diamond coatings were electrodeposited onto steel substrates using a pulse-stirring method. The electrodeposition process involved a solution containing nickel sulphate, phosphorus acid, and diamond particles, resulting in the co-electrodeposition of 4-8 µm of diamond particles into a Ni-P matrix. To investigate the effects of electrodeposition current density on the properties of the Ni-P/diamond composite coating, scanning electron microscopy (SEM), hardness testing, and electrochemical testing were employed. The research findings revealed that higher current density (0.03 A/cm²) led to a denser diamond particle coating with diamond contents of up to 32.70 vol%. Additionally, the Ni-P/diamond coatings achieved a maximum hardness of 2819 ± 12.55 HV_0.1 when fabricated using the current density of 0.03 A/cm². The "pulse-stirring fabrication" method yields a coating with significantly enhanced wear resistance due to incorporating densely packed diamond particles. The intermittent pulses during the fabrication process are crucial for achieving the desired dispersion and adhesion of the diamond particles, leading to a practical and durable wear-resistant coating.