Optimization of a high-pressure microwave curing process for T800/X850 carbon fiber-reinforced plastic

2019 ◽  
Vol 32 (1) ◽  
pp. 30-38 ◽  
Author(s):  
Chenglong Guan ◽  
Lihua Zhan ◽  
Guiming Liu ◽  
Xiaobo Yang ◽  
Guangming Dai ◽  
...  
Keyword(s):  
High Pressure ◽  
Heating Rate ◽  
Process Parameters ◽  
Holding Time ◽  
Curing Temperature ◽  
Measurement Capability ◽  
Microwave Curing ◽  
Trade Offs ◽  
Input Control ◽  
Interlaminar Shear

Compared with the conventional composite curing processes, high-pressure microwave curing is a promising technology. In this study, a set of devices for high-pressure microwave curing was built and equipped with real-time temperature measurement capability and a microwave input control system. The orthogonal experimental method was applied to optimize three process parameters, including the heating rate, curing temperature, and holding time, for the high-pressure microwave curing of T800/X850 composites. The effects of the three parameters on the curing quality were studied by measuring the interlaminar shear strength (ILSS) and conducting differential scanning calorimeter tests. The fracture surface of the samples was also examined by scanning electron microscopy. The results showed that the heating rate had a significant effect on the ILSS of the laminates, and the degree of cure of all samples was more than 95% in the tests. Furthermore, the optimal process parameters were determined as follows: heat up to 170°C with a heating rate of 6°C min−1 and a holding time of 90 min. The total curing time of the sample was 42.4%, and the ILSS of the sample was slightly enhanced by 0.31% compared with standard thermal curing. These results could serve to make trade-offs between reducing manufacturing time and preserving the mechanical properties of microwave-cured composites.

scholarly journals Microwave Sintering of Ti6Al4V: Optimization of Processing Parameters for Maximal Tensile Strength and Minimal Pore Size

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1086 ◽  
Author(s):  
Dilpreet Singh ◽  
Abhishek Rana ◽  
Pawan Sharma ◽  
Pulak Mohan Pandey ◽  
Dinesh Kalyanasundaram
Keyword(s):  
Tensile Strength ◽  
Pore Size ◽  
Heating Rate ◽  
Process Parameters ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Compressive Force ◽  
Holding Time ◽  
Minimum Size ◽  
Optimal Process

Pressureless sintering is a powder metallurgical process wherein the powder particles are sintered without the aid of any compressive force. Though this additive manufacturing process is economical, the strength of the component is undermined due to the presence of pores; the elimination of which is a challenge. In this work, the optimal process parameters for the pressureless microwave sintering of a grade 5 titanium alloy that yields higher tensile strength and minimum sizes of pores were obtained. The three process parameters (sintering temperature, heating rate, and holding time) were experimented at five different levels using the design of experiments (DOE). Post sintering, the tensile strength was assessed as per ASTM standard B925-15, while the pore size was evaluated, non-destructively, using micro-computed tomography (μ-CT). The optimal process parameters that yielded minimum size pores were: sintering temperature—1293 °C, heating rate— 6.65 C/minute; and holding time—72 min.

Study of the influence of microwave sintering parameters on the mechanical behaviour of magnesium-based metal matrix composite

2020 ◽  
pp. 095440622095123 ◽  
Author(s):  
Ajit Kumar ◽  
Pulak M Pandey
Keyword(s):  
Metal Matrix Composite ◽  
Heating Rate ◽  
Matrix Composite ◽  
Process Parameters ◽  
Metal Matrix ◽  
Sintered Density ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Holding Time ◽  
X Ray

In the present work, initially, the microwave sintering was used to fabricate a magnesium-based metal matrix composite (MgMMCs) especially Mg3Zn1Ca15Nb, at the same process parameters which were used to develop aforesaid material using conventional sintering. But, no improvement in the results were found, which may be owing to non-optimized parameters of microwave sintering. To carry out the optimization of microwave sintering parameters, first, the range of process parameters was obtained in this study. Sintering temperature (ST), heating rate (HR), and holding time (HT) were selected as sintering parameters. Additionally, the effects of these parameters on the ultimate compressive strength (UCS) as well as the sintered density of Mg3Zn1Ca15Nb were studied. After performing the compression test on the sintered samples (Ø10 × 15 mm2), an increment in both density and UCS was noted with the increase in sintering temperature and heating rate. Whereas sintering the sample above a certain period of holding time, the downward inclination of both UCS and sintered density was observed. The obtained UCS, as well as the density of microwave sintered samples were in the range of orthopedic implantable materials. The images obtained from scanning electron microscopy (SEM) affirmed the reduced porosity in the sintered samples as the heating rate increased. Additionally, a combined reduction in agglomeration, as well as cracks in the fabricated sample was observed by increasing sintering temperature. Energy-dispersive X-ray (EDX) study of the microwave fabricated Mg3Zn1Ca15Nb exhibited the presence of only parent elements in the fabricated sample. Also, no phase constituent was recorded in the fabricated sample, as confirmed by X-ray diffraction (XRD) spectra.

The effect of moulding process parameters on interlaminar properties of CF/PEEK composite laminates

2020 ◽  
Vol 32 (7) ◽  
pp. 835-841 ◽  
Author(s):  
Guangming Dai ◽  
Lihua Zhan ◽  
Chenglong Guan ◽  
Minghui Huang
Keyword(s):  
Process Parameters ◽  
Composite Laminates ◽  
Failure Modes ◽  
Shear Failure ◽  
Holding Time ◽  
Thermoplastic Composite ◽  
Moulding Process ◽  
Peek Composite ◽  
Moulding Pressure ◽  
Interlaminar Shear

Interlaminar properties are one of the most important indicators of thermoplastic composite quality. A series of laminates with different moulding process parameters were prepared by unidirectional carbon fibre-reinforced polyether ether ketone (CF/PEEK) prepreg to explore the influence of moulding process parameters on the interlaminar properties of CF/PEEK composite laminates. The influence of the three process parameters, moulding pressure, moulding temperature, and holding time on the interlaminar shear strength (ILSS) of [0/90]8 laminates was studied. The interlaminar shear failure modes of specimens under different moulding process parameters were compared, and the correlation between the ILSS and interlaminar shear failure modes was analysed. The results showed that the appropriate moulding pressure was 2 MPa, the proper moulding temperature range was 400–420°C and the holding time should not be less than 20 min. The main failure modes were tensile or compression when the laminates were moulded using proper process parameters; interlaminar shear failure might also appear in those moulded by non-optimised process parameters.

scholarly journals Optimization of Sintering Process of Alumina Ceramics Using Response Surface Methodology

2021 ◽  
Vol 13 (12) ◽  
pp. 6739
Author(s):  
Darko Landek ◽  
Lidija Ćurković ◽  
Ivana Gabelica ◽  
Mihone Kerolli Mustafa ◽  
Irena Žmak
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Heating Rate ◽  
Sintering Temperature ◽  
Nonlinear Models ◽  
Slip Casting ◽  
Holding Time ◽  
Alumina Ceramics ◽  
Aqueous Suspensions ◽  
Temperature Heating

In this work, alumina (Al2O3) ceramics were prepared using an environmentally friendly slip casting method. To this end, highly concentrated (70 wt.%) aqueous suspensions of alumina (Al2O3) were prepared with different amounts of the ammonium salt of a polycarboxylic acid, Dolapix CE 64, as an electrosteric dispersant. The stability of highly concentrated Al2O3 aqueous suspensions was monitored by viscosity measurements. Green bodies (ceramics before sintering) were obtained by pouring the stable Al2O3 aqueous suspensions into dry porous plaster molds. The obtained Al2O3 ceramic green bodies were sintered in the electric furnace. Analysis of the effect of three sintering parameters (sintering temperature, heating rate and holding time) on the density of alumina ceramics was performed using the response surface methodology (RSM), based on experimental data obtained according to Box–Behnken experimental design, using the software Design-Expert. From the statistical analysis, linear and nonlinear models with added first-order interaction were developed for prediction and optimization of density-dependent variables: sintering temperature, heating rate and holding time.

scholarly journals Salt Distribution and Salt Uptake during Ripening in Turkish White Cheese Affected by High Pressure Processing

2018 ◽  
Vol 6 (4) ◽  
pp. 433
Author(s):  
Nurcan Koca ◽  
Raghu Ramaswamy ◽  
W.M. Balasubramaniam ◽  
W. James Harper
Keyword(s):  
High Pressure ◽  
Pressure Effect ◽  
High Pressure Processing ◽  
Holding Time ◽  
Salt Uptake ◽  
White Cheese ◽  
Textural Changes ◽  
Salt Distribution ◽  
High Pressure Effect

Turkish white cheeses after brine salting were subjected to high pressure processing (HPP) at 50, 100, 200 and 400 MPa for 5 and 15 min and the samples pressurized for 15 min were ripened in brine for 60 days. The effects of HPP on the salt distribution in external, middle and internal zones of cheese after pressurization and on the salt uptake of whole cheese block during ripening were investigated. HPP did not change the values of moisture, salt and salt in moisture in different zones of cheese. Furthermore, pressure holding time had no effect on salt distribution in cheese. The salt contents of un-pressurized and pressurized cheese samples were equilibrated on the 14th day of ripening, and then stabilized, with no high pressure effect. As a result, HPP at pressures up to 400 MPa did not significantly affect neither salt distribution after high pressure processing nor salt uptake during ripening. However, a slight increase in moisture at the pressures of 200-400 MPa on the 60th day of ripening, which was not significant, might warn further increases in moisture of white cheese for longer ripening periods than 60 days. Higher pressure applications may alter all those values in white cheese because of textural changes.

scholarly journals Hydration and Microwave Curing Temperature Interactions of Repair Mortars

2021 ◽  
Vol 03 (04) ◽  
pp. 1-1
Author(s):  
Pal S. Mangat ◽  
◽  
Shahriar Abubakri ◽  
Konstantinos Grigoriadis ◽  
Vincenzo Starinieri ◽  
...  
Keyword(s):  
Portland Cement ◽  
Heat Of Hydration ◽  
Curing Temperature ◽  
Early Age ◽  
Normal Density ◽  
Concrete Repair ◽  
Microwave Curing ◽  
Polymer Addition ◽  
Curing Period ◽  
Repair Materials

Microwave curing of repair patches provides an energy efficient technique for rapid concrete repair. It has serious economic potential due to time and energy saving especially for repairs in cold weather which can cause work stoppages. However, the high temperatures resulting from the combination of microwave exposure and accelerated hydration of cementitious repair materials need to be investigated to prevent potential durability problems in concrete patch repairs. This paper investigates the time and magnitude of the peak hydration temperature during microwave curing (MC) of six cement based concrete repair materials and a CEM II mortar. Repair material specimens were microwave cured to a surface temperature of 40-45 °C while their internal and surface temperatures were monitored. Their internal temperature was further monitored up to 24 hours in order to determine the effect of microwave curing on the heat of hydration. The results show that a short period of early age microwave curing increases the hydration temperature and brings forward the peak heat of hydration time relative to the control specimens which are continuously exposed to ambient conditions (20 °C, 60% RH). The peak heat of hydration of normal density, rapid hardening Portland cement based repair materials with either pfa or polymer addition almost merges with the end of microwave curing period. Similarly, lightweight polymer modified repair materials also develop heat of hydration rapidly which almost merges with the end of microwave curing period. The peak heat of hydration of normal density ordinary Portland cement based repair materials, with and without polymer addition, occurs during the post microwave curing period. The sum of the microwave curing and heat of hydration temperatures can easily exceed the limit of about 70 °C in some materials at very early age, which can cause durability problems.

Transient Thermal Modeling of In-Situ Curing During Tape Winding of Composite Cylinders

2003 ◽  
Vol 125 (1) ◽  
pp. 137-146 ◽  
Author(s):  
Jonghyun Kim ◽  
Tess J. Moon ◽  
John R. Howell
Keyword(s):  
Process Parameters ◽  
Moving Boundary ◽  
Curing Temperature ◽  
Heat Transfer Analysis ◽  
Temperature History ◽  
Maximum Temperature ◽  
Degree Of Cure ◽  
Orthotropic Composites ◽  
Composite Cylinders

Fully-transient, two-dimensional, heat transfer analysis for the simultaneous tape winding and in-situ curing of composite cylinders is presented. During processing, the orthotropic composites are continuously wound onto an isotropic mandrel and cured simultaneously by infrared (IR) heating. To most efficiently and effectively consider the continual accretion of composite, the model is formulated within a Lagrangian reference frame in which the heating source rotates while the coordinate system and composite are stationary. This enables prediction of composite temperature and degree-of-cure history from the first to last layer. Separate heat conduction equations are formulated for both the mandrel and composite cylinder. The composite cylinder’s outer surface is modeled as a moving boundary due to the accumulated layers. Exothermic heat generation due to the epoxy resin’s chemical reaction is included as a function of temperature and degree of cure. Numerical simulations using a control-volume-based finite difference method are run for a common graphite/epoxy (AS4/3501-6) composite. The Lagrangian approach was found to more accurately predict the in-situ curing temperature and degree-of-cure histories than the previously used, quasi-steady-state Eulerian approaches, which underpredict thermal losses. The model and its computational implementation were verified using analytical solutions and actual experiments. During winding, the top layer’s maximum temperature increases with total number of layers wound, demonstrating that a given incoming prepreg tape’s temperature history evolves with time. Moreover, with appropriate mandrel preheating, the inner layers can reach a very high degree of cure by the end of the winding process, revealing that the mandrel’s initial temperature has a significant effect on the composite’s temperature and degree-of-cure history. Substantial increases in the winding speed have little or no effect on the composite’s temperature history, but can significantly reduce the corresponding degree-of-cure. The development of structurally debilitating residual stresses are an important concern in selecting process parameters, such as winding speed and heating power. Taking advantage of the strong correlation between winding speed and IR heat flux, process windows can be used to guide the selection of manufacturing process parameters. These definitively show that there are thermodynamically imposed limits on how fast the cylinders may be wound and radiatively cured.

Sign in / Sign up

Export Citation Format

Share Document