Papers by Keyword: Heating Rate

Abstract: Solid-phase deposition (SPD) is a preferable method to fabricate multi-layer graphene (MLG) for device applications since MLG can be deposited directly on substrates without transfer. Previously, we reported that current application during SPD enhances the MLG growth. In this study, we investigated the effects of applied current and heating rate on the crystallinity and uniformity of MLG precipitated from carbon (C) / nickel (Ni) structures. It was found that higher current and slower heating rate lead to improve the MLG crystallinity. Moreover, the uniformity was improved by the optimization of Ni and C thickness which could control the nucleation and growth of MLG during SPD. As a result, a uniform MLG with a high G/D ratio of 5.5 was obtained at a low temperature of 365 °C.

Abstract: This contribution presents a study on the effect of heating rate maintained during annealing treatment on the final microstructure and mechanical properties of cold rolled Al1050 sheet. This study is focused on microstructure and texture evolution of Al1050 annealed at various heating rates, annealing temperatures, and holding times. It was observed that the longer exposure time for deformed microstructure affects the Vickers hardness values, grain size, and texture intensity. It seems that the crystallographic texture evolution is not affected by heating rate on quantitative level since the same set of orientations tended to evolve in all studied cases. The sample annealed at slow heating rate in a box-type furnace produced recrystallized microstructure with fine grain size, and comparatively lower texture intensity & hardness.

Abstract: In the injection molding process, the filling process will be easier and, in most cases, the surface quality will be significantly improved if the mold surface temperature is high. However, as the temperature of the mold plates rises, the cooling process takes longer, the injection molding cycle takes longer, and the cost of production rises. The most important thing is to keep the mold temperature under control, which means heating the mold surface to the required temperature while keeping the injection cycle time to a minimum. In this research, hot air was used as the heat source for raising the cavity temperature to over 200 °C with a heating time of 20 s. At the end of heating process, the temperature was collected at 10 points for comparison. In addition, the temperature distribution was also discussed.

Abstract: In view of the climate emergency and the need for energy transition, the use of materials with low environmental impact based on plant co-products or from recycling is strongly encouraged. Biobased materials have been developed in recent years and have shown interesting performances, particularly for the thermal insulation of buildings. Nevertheless, their use is still hampered by the lack of rules for their use and control of their behaviour in normal or accidental conditions of use such as excess water or fire. In this work, the behaviour of biocomposites based on cereal straw exposed to high temperatures was studied. The objective is to evaluate the effect of this temperature increase on the mechanical strength of the material and its thermal properties using different heating scenarios. The biocomposites considered for this study were developed as part of the PEPITE project funded by the “Region Centre Val de Loire”. They are materials composed of two different binders: lime, and plaster, straw aggregates and additives (air entraining agent, casein protein and biopolymer). In order to simulate fire, two temperatures were chosen for the study 200°C and 210°C, using four different heating rates to study their impact on the behaviour of dry and wet conditions of biocomposites. The purpose of this tests is to examine whether the material retains its insulating properties and its buildability. The results showed that the use of additives had negative effects on the behaviour of the materials with respect to temperature increase. Their use accelerates the degradation and burning of biocomposites faster than for samples without additives. Plaster based composites show a better behavior to high temperature than lime-based composites. Nevertheless, lime composites have a higher strength than plasters. Furthermore, the thermal conductivity of plaster is lower than that of lime. It should be noted that the heating rate has a significant impact on the behaviour of the material, the slower the rate, the more the material is degraded.

Abstract: Vibration systems require the damping materials operating at high service temperature. In this paper, damping performance of HT100, M2052 and S316L at 350K were evaluated by applying different frequencies, strain amplitudes and heating rates. It is found that the internal friction dependence of frequency of HT100, M2052 and S316L all show a characteristic of Check function, and the resonance frequency has a negative linear correlation with the material physical parameters. The strain amplitude as well as heating rate has no obvious effect on the resonance frequencies of the materials, but significantly enhance the internal friction of the interface damping alloys such as M2052 and HT100, but small on single-phase alloys such as S316L. The internal friction mechanism for HT100 and M2052 are of static hysteresis at 350K, and HT100 and M2052 are applicable candidates for working at temperatures around 350K from the viewpoint of vibration reduction.

Abstract: Typical applications of ferritic stainless steels require good formability of the material that is highly dependent on the processing route. In this study, the effects of the heating rate and peak heating temperature on the texture and deep drawability (R-value) of a 78% cold rolled, stabilized 18Cr (AISI 441) ferritic stainless steel were studied. Pieces of cold rolled sheet were heated in a Gleeble 3800 simulator at the heating rates of 25 °C/s and 500 °C/s to various temperatures up to 1150 °C for 10 s holding before cooling at a rate of 35 °C/s. Microstructures were characterized and the texture of the annealed samples determined by the electron backscatter diffraction method. It was established that the high heating rate of 500 °C/s promotes the nucleation of grains with the near {111}<uvw> orientations during the early state of the recrystallization. The maximum texture intensities were found at {554}<225>. The more effective nucleation of these grains resulted in a finer grain size and an increased intensity of the gamma-fibre texture which led to enhanced R-values. At high peak temperatures, the intense grain growth took place.

Abstract: Aluminum metal matrix composites (Al-MMCs) is a one of the most demanding engineering material due to the combination of their light weight, excellent mechanical and tribological properties. To enhance the promising advantages of Al-MMCs, microwave sintering (MWS) is an ideal and emerging technique. The unique advantages of MWS of MMCs are ascribed to the size and distribution of the reinforcement, as well as to the grain size of the matrix along with uniform and efficient heating. The objective of this comprehensive review was to highlight the viability of sintering Al-MMC in a microwave oven, and compare the material characteristics of those with similar materials sintered in a conventional furnace.

Abstract: Lead-free powders of Bi(Na_0.81K_0.19)O₃ doped 0.3 wt.% CoO were prepared by a conventional mixed oxide technique. The sintering process was controlled with various rate up and down temperature. The samples were sintered at 1,050 °C for 4 h which difference heating rate controlled i.e. 100, 300, and 600 °C/h. The XRD pattern analysis of all studied samples showed a single phase perovskite structure Dielectric and ferroelectric properties of the ceramics were investigated as a function of rate controlled sintering temperature. The sample heating rate at 600 °C/h showed maximum dielectric constant (~5961) at T_m. In addition, the ferroelectric properties were analyzed and discussed.

Abstract: Generally, metal injection molding (MIM) method utilizes SS 17-4 PH as material for application of orthodontic bracket. One of the process of MIM is thermal debinding, which binder is eliminated by thermal energy. In this study, thermal debinding process is conducted with variation of temperature, i.e. 480, 510, and 540°C, holding time, i.e. 0.5, 1 and 2 hours, heating rate, i.e. 0.5, 1, 1.5, and 2°C/min.The effect of temperature shows that the increased temperature will result in the mass reduction percentage due to formation of oxide on the sample, which will be proven through TGA testing. The highest mass reduction was 6.4137 wt% which was obtained at 480°C. For the variation of holding time, the longer the holding time will result in increased mass reduction and the highest mas reduction was 6.255 wt% which was obtained during 2 hours of holding time. For the heating rate, the slower the heating rate will result in increased mass reduction and decreased the presence of crack formation. The best variable was obtained at heating rate of 0.5°C/min, which resulted mass reduction of 6.2488 wt% and less crack formation.

Abstract: This aim of this work was to evaluate the influences of the heating rates and sintering temperatures for sintering β-TCP by microwave furnace. In the first part of work, the heating rates used for sintering β-TCP were including 10, 20, 30 and 40°C/min. Results from physical and mechanical analysis shown that the optimum properties were shown by samples produced at heating rate of 30°C/min. In the second part of the study, the heating rate of 30°C/min was continuing used to sintering samples by different temperatures (1200°C, 1250°C and 1300°C). The sintered sample at 1200°C presented the optimum properties in the physical and mechanical analysis. Finally, the sintered samples by the heating rate 30°C/min at 1200°C were in immersed in SBF to confirm the bioactivity property of β-TCP.