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.

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 Experimental Investigation and Optimization of the Semisolid Multicavity Squeeze Casting Process for Wrought Aluminum Alloy Scroll

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5278
Author(s):  
Yi Guo ◽  
Yongfei Wang ◽  
Shengdun Zhao
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Process Parameters ◽  
Squeeze Casting ◽  
Shrinkage Porosity ◽  
Optimal Process ◽  
Squeeze Pressure ◽  
Wrought Aluminum

Scroll compressors are popularly applied in air-conditioning systems. The conventional fabrication process causes gas and shrinkage porosity in the scroll. In this paper, the electromagnetic stirring (EMS)-based semisolid multicavity squeeze casting (SMSC) process is proposed for effectively manufacturing wrought aluminum alloy scrolls. Insulation temperature, squeeze pressure, and the treatment of the micromorphology and mechanical properties of the scroll were investigated experimentally. It was found that reducing the insulation temperature can decrease the grain size, increase the shape factor, and improve mechanical properties. The minimum grain size was found as 111 ± 3 μm at the insulation temperature of 595 °C. The maximum tensile strength, yield strength, and hardness were observed as 386 ± 8 MPa, 228 ± 5 MPa, and 117 ± 5 HV, respectively, at the squeeze pressure of 100 MPa. The tensile strength and hardness of the scroll could be improved, and the elongation was reduced by the T6 heat treatment. The optimal process parameters are recommended at an insulation temperature in the range of 595–600 °C and a squeeze pressure of 100 MPa. Under the optimal process parameters, scroll casting was completely filled, and there was no obvious shrinkage defect observed inside. Its microstructure is composed of fine and spherical grains.

Preparation of Porous Wollastonite Ceramics for Filtration

2007 ◽  
Vol 336-338 ◽  
pp. 1102-1104 ◽  
Author(s):  
Ming Sheng He ◽  
Jian Bao Li ◽  
Bo Wen Li ◽  
Hong Lin ◽  
Xiao Zhan Yang ◽  
...  
Keyword(s):  
Specific Surface ◽  
Pore Size ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sintering Temperature ◽  
Porous Ceramics ◽  
Holding Time ◽  
Starting Material ◽  
Sintering Method

Wollastonite powder was selected as a starting material with carbonate as pore-forming agent and binder added. The porous ceramics were prepared at different temperature by sintering method. The process includes batching, granulating, pressing molding, drying and sintering. It is discussed the influence of sintering temperature, dosage of binder, dosage of pore-forming agent, pressure of molding and holding time on the performance of porous ceramics. According to the principle of particles stack, the porous wollastonite ceramics for filtration with various diameters, shapes and porosity were fabricated by serial experiments. These products have 1 to 10 microns in pore size, 30.04 to 66.15% in porosity, 2.82 m2/g in specific surface area.

scholarly journals Dilation of Ti-6Al-4V/HA Composite Tensile Parts

2002 ◽  
Vol 11 (2) ◽  
pp. 096369350201100
Author(s):  
E. S. Thian ◽  
N. H. Loh ◽  
K. A. Khor ◽  
S. B. Tor
Keyword(s):  
Heating Rate ◽  
Sintering Temperature ◽  
Holding Time ◽  
Test Results ◽  
Basic Information ◽  
Sintering Process ◽  
Densification Rate ◽  
In Situ Test ◽  
Temperature Heating

Prior to the actual sintering process, a dilatometry study is performed to provide basic information and guidelines. This paper studies the effects of three sintering factors: sintering temperature, heating rate and holding time, on the densification rate of Ti-6Al-4V/HA composite parts. According to the in-situ test results, suitable values for the sintering factors can then be established.

scholarly journals Experimental investigations into mechanical and thermal properties of rapid manufactured copper parts

2019 ◽  
Vol 234 (1) ◽  
pp. 82-95 ◽  
Author(s):  
Gurminder Singh ◽  
Pulak M Pandey
Keyword(s):  
Thermal Conductivity ◽  
Tensile Strength ◽  
Thermal Properties ◽  
Ultimate Tensile Strength ◽  
Heating Rate ◽  
Sintering Temperature ◽  
Mechanical And Thermal Properties ◽  
Surface Porosity ◽  
Soaking Time ◽  
Ultrasonic Assisted

In the present paper, mechanical and thermal properties of rapidly manufactured copper parts were studied. The combination of three-dimensional printing and ultrasonic assisted pressureless sintering was used to fabricate copper parts. First, the ultimate tensile strength and thermal conductivity were compared between ultrasonic assisted and conventional pressureless sintered samples. The homogenously mixing of particles and local heat generation by ultrasonic vibrations promoted the sintering driving process and resulted in better mechanical and thermal properties. Furthermore, response surface methodology was adopted for the comprehensive study of the ultrasonic sintering parameters (sintering temperature, heating rate, and soaking time with ultrasonic vibrations) on ultimate tensile strength and thermal conductivity of the fabricated sample. Analysis of variance was performed to identify the significant factors and interactions. The image processing method was used to identify the surface porosity at different parameter levels to analyse the experimental results. High ultimate tensile strength was obtained at high sintering temperature, long soaking time, and slow heating rate with low surface porosity. After 60 min of soaking time, no significant effect was observed on the thermal conductivity of the fabricated sample. The significant interactions revealed less effect of soaking time at low sintering temperatures for ultimate tensile strength and less effect of heating rate at low sintering temperatures for thermal conductivity. Multi-objective optimization was carried out to identify parameters for maximum ultimate tensile strength and maximum thermal conductivity.

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 Effects of Microwave Sintering Temperature and Holding Time on Mechanical Properties and Microstructure of Si3N4/n-SiC ceramics

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3837 ◽  
Author(s):  
Li Qiao ◽  
Zhenhua Wang ◽  
Taiyi Lu ◽  
Juntang Yuan
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Phase Formation ◽  
Mechanical Performance ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Holding Time ◽  
Sic Ceramics ◽  
Si3n4 Ceramics

The n-SiC (nanometer SiC) is added to be the additive in order to improve the mechanical performance of Si3N4 ceramics. A microwave sintered the ceramics at different temperature and holding times. The results shows that the Si3N4/n-SiC ceramics (85 wt% Si3N4 + 5 wt% n-SiC + 5 wt% Al2O3 + 5 wt% Y2O3) have the best mechanical properties at 1600 °C, which is beneficial to the densification and β-Si3N4 phase formation for 10 min: the density, hardness, and fracture toughness were 97.1%, 14.44 GPa, and 7.77 MPa·m1/2, which increased by 2.8%, 7.0%, and 13.1%, respectively, when compared with the ceramics (90 wt% Si3N4 + 5 wt% Al2O3 + 5 wt% Y2O3).

Fabrication and Compressive Properties of Titanium Foam for Bone Implant Applications

2018 ◽  
Vol 770 ◽  
pp. 126-131 ◽  
Author(s):  
Zeng Feng Li ◽  
Chen Wu ◽  
Gang Chen ◽  
Ping Tan ◽  
Shao Yang Zhao ◽  
...  
Keyword(s):  
Yield Strength ◽  
Pore Structure ◽  
Pore Size ◽  
Young’S Modulus ◽  
Sintering Temperature ◽  
Young's Modulus ◽  
Holding Time ◽  
Powder Metallurgy Method ◽  
Compressive Properties ◽  
Titanium Foam

In order to meet the requirements for the purpose of biological implant materials, analyzes the matching requirements of the compatibility and mechanical properties of titanium foam biological; by powder metallurgy method, using TiH2 powder as raw material, using ammonium bicarbonate as pore forming agent, preparation of titanium foam. The influences of pore forming agent content and particle size, sintering temperature and holding time on the pore structure, pore distribution, pore size and compressive properties of foam titanium were discussed in detail. The results show that with the increase of the sintering temperature and prolonging holding time, titanium foam compressive yield strength and modulus increased; with the increase of the content of pore forming agent, titanium foam compression yield strength and Young's modulus decreased. The preparation of a porosity of 48% ~ 77%, pore size between 300 ~ 500 m, foam pore structure and pore size in micron level through three-dimensional pore, pore size of bio materials meet the requirements. The compressive strength is 98~186MPa, and the young's modulus is 1.6 ~ 6.8 GPa, which matches the strength and the modulus of elasticity of biological implants.

scholarly journals Multiobjective Optimization for Forming Process Parameters of Ultrahigh Strength Steel BR1500HS

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Xin Shang ◽  
Lijuan Pang ◽  
Sheng-Gui Chen
Keyword(s):  
Experimental Data ◽  
Tensile Strength ◽  
Process Parameters ◽  
Holding Time ◽  
Optimum Process ◽  
Forming Process ◽  
Martensite Content ◽  
Ultrahigh Strength ◽  
Ultrahigh Strength Steel ◽  
Optimal Value

This paper focuses on obtaining the optimum process parameters and improving the mechanical properties of ultrahigh strength steel BR1500S. Many experimental data are obtained, and then response surface methodology (RSM) is used to obtain the optimum parameters. Combining the experimental data with RSM, some conclusions are summarized. When the cooling rate reaches 30°C/s, martensite content in microstructure reaches up to 95%. The optimum regions of quenching hardness, tensile strength, and elongation are obtained when the temperature is about 900°C, and the holding time is about 0∼4 min. Results of multiobjective optimizations show that global optimal value is gained at 906.5°C, and the holding time is 0 min. Predicted optimum values of quenching hardness, tensile strength, and elongation are not less than 51.03 HRC, 1,671 MPa, and 8.75%, respectively. The application of RSM is notably successful in predicting the process parameters of hot forming.

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