An experimental investigation of the fabrication of biodegradable zinc–hydroxyapatite composite material using microwave sintering

2020 ◽  
Vol 234 (14) ◽  
pp. 2863-2880 ◽  
Author(s):  
Dayanidhi Krishana Pathak ◽  
Pulak Mohan Pandey
Keyword(s):  
Yield Strength ◽  
Heating Rate ◽  
Sintered Density ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Compaction Pressure ◽  
Optimum Process ◽  
Compressive Yield Strength ◽  
Process Factors

The present work focuses on the fabrication of zinc–hydroxyapatite biodegradable composite with the use of pressureless microwave sintering for the orthopedic load-bearing application. The samples were prepared using the powder metallurgy process. The powders of both materials were homogeneously mixed in the quantified proportions to form the uniform mixture. For the fabrication of samples, the planning of experiments was done with the central composite design. The effect of process factors such as the weight percentage of hydroxyapatite, compaction pressure, and microwave sintering factors such as sintering temperature, heating rate, and soaking time on the compressive yield strength and sintered density was evaluated. Cylindrical samples were prepared for compression testing. The experimental results exhibited the increase in the compressive yield strength as well as the sintered density with the decrease in the hydroxyapatite percentage and an increase in the compaction pressure. The results also revealed that the compressive yield strength and sintered density were found to be increased as the heating rate and sintering temperature increased. Sample characterization was carried out for phase determination and composition of the elements. The optimum process factors were obtained after the regression analysis, and the results of the optimum process factors were also verified with the confirmation experiments. The in vitro corrosion testing of the sample prepared with optimum factors was also carried out in the simulated body fluid at a temperature of 37 ± 0.5 ℃. The fabricated sample showed a good agreement between the mechanical and degradation properties as required for a human bone.

Rapid manufacturing of biodegradable pure iron scaffold using amalgamation of three-dimensional printing and pressureless microwave sintering

2018 ◽  
Vol 233 (6) ◽  
pp. 1876-1895 ◽  
Author(s):  
Pawan Sharma ◽  
Pulak M Pandey
Keyword(s):  
Yield Strength ◽  
Sintered Density ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Three Dimensional ◽  
Rapid Tooling ◽  
Compressive Yield Strength ◽  
Soaking Time ◽  
Three Dimensional Printing ◽  
Dimensional Printing

In the present work, a rapid tooling process using three-dimensional printing and pressureless microwave sintering has been developed for the fabrication of biodegradable pure iron. Carbonyl iron particles were used for sample preparation and phosphate-based investment material was used for mould fabrication. Cylindrical samples were fabricated successfully using the developed rapid tooling process. The fabrication experiments were planned based on response surface methodology to evaluate the effect of microwave sintering parameters, namely sintering temperature, heating rate and soaking time on sintered density, shrinkage and compressive yield strength. The results showed that sintered density and compressive yield strength increased with the rise in sintering temperature from α to γ iron transformation temperature and were found to decrease with further rise in temperature. The shrinkage was found to increase with the increase in sintering temperature. Moreover, with the increase in soaking time and decrease in heating rate, sintered density, shrinkage and compressive yield strength were found to increase. Scanning electron microscopy and the X-ray diffraction plot of the fabricated iron samples showed that even without the application of pressure proper bonding of carbonyl iron particles was achieved. Mould material contamination or oxidation was not evidenced in the experiments. A multi-objective optimization using genetic algorithm was performed to obtain optimum microwave sintering parameters for maximum sintered density as well as compressive strength and minimum shrinkage. A case study on the fabrication of scaffold for human skull was performed to test the efficacy of the developed rapid tooling process.

Effect of sintering parameters on the microstructure and compressive mechanical properties of porous Fe scaffold fabricated using 3D printing and pressure less microwave sintering

2020 ◽  
Vol 234 (21) ◽  
pp. 4305-4320
Author(s):  
Dipesh Kumar Mishra ◽  
Pulak Mohan Pandey
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Heating Rate ◽  
Sintering Temperature ◽  
Electron Backscatter Diffraction ◽  
Microwave Sintering ◽  
Compressive Yield Strength ◽  
Soaking Time ◽  
Electron Backscatter ◽  
Backscatter Diffraction

The demand for the porous scaffold has been increasing globally in the biomedical field due to numerous advantages over dense structures like high damping capacity, high specific strength, and improved cell integration growth. In the present study, porous iron scaffolds were fabricated using micro-extrusion-based three-dimensional printing and pressureless microwave sintering. For the preparation of samples, metal-based polymeric ink was developed. Thereafter, cylindrical samples were printed and then sintered in a microwave sintering furnace. The experimental investigations were performed to estimate the effect of sintering parameters such as sintering temperature, heating rate and soaking time on the compressive and microstructural property of the fabricated samples. Microstructural characterization was done using the electron backscatter diffraction technique. The experimental observations deduced that the compressive yield strength and apparent density of the sintered sample increased with the increase in sintering temperature and decreased with a further rise in temperature. Moreover, the electron backscatter diffraction analysis unveiled that the high heating rate resulted in the reduction of compressive yield strength due to rapid grain growth. Additionally, the significant effect of soaking time on the compressive mechanical properties was also noticed due to the increase in the grain size diameter. From the X-ray diffraction plot, it was found that there was no contamination present in the fabricated scaffold. In order to evaluate the process capability, a case study was performed wherein the topologically ordered porous structure of iron was fabricated at optimum sintering parameters.

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 Influence of Various Process Parameters on the Density of Sintered Aluminium Alloys

10.14311/1604 ◽  
2012 ◽  
Vol 52 (4) ◽  
Author(s):  
Mateusz Laska ◽  
Jan Kazior
Keyword(s):  
Sintered Density ◽  
Sintering Temperature ◽  
Compaction Pressure ◽  
Nitrogen Atmosphere ◽  
Chemical Compositions ◽  
Green Density ◽  
Heating And Cooling ◽  
Wide Range ◽  
Different Temperatures ◽  
Metallurgy Industry

This paper presents the results of density measurements carried out on Alumix sintered parts. ECKA Alumix aluminium powders were used because of their wide application in the powder metallurgy industry. The compacts were produced using a wide range of compaction pressures for three different chemical compositions. The compacts were then sintered under a pure dry nitrogen atmosphere at three different temperatures. The heating and cooling rates were the same throughout the entire test. The results showed that the green density increases with compaction pressure, but that sintered density is independent of green density (compaction pressure) for each sintering temperature.

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.

Effects of Sintering Temperature on the Properties of Cu-Co-Based Alloys Matrix

2011 ◽  
Vol 201-203 ◽  
pp. 1757-1762 ◽  
Author(s):  
Yang Lu ◽  
Hong Feng Dong ◽  
Wen Sheng Li
Keyword(s):  
Yield Strength ◽  
Metal Matrix ◽  
Sintering Temperature ◽  
Cutting Tools ◽  
Cobalt Content ◽  
Compressive Yield Strength ◽  
Binary Solid Solution ◽  
Alloy Matrix ◽  
New Generation ◽  
Structural Aspects

Cu–Co–based alloys are the new generation of metal matrix for diamonds by powder metallurgy processed cutting tools. These alloys are created with the purpose of reducing the cobalt content in diamond tools. Cu-Co-based alloys matrix were fabricated using a hot pressing process at the temperature of 710°C , 750°С and 790°С by 15 MPa. Structures formed during sintering were studied by XRD and WDS. Micro-structural aspects were observed by EPMA. Densification, hardness, yield strength and compressive yield strength were performed. The results showed as follows: Cu-Co-based alloy matrix is composed by gray pre-alloyed particles, Cu-Sn binary solid solution, copper-rich phase and interface between particles and matrix; The higher sintering temperature, the more dendrite phase, in addition, the diffusion of carbon occurs; the holding force from matrix to particles becomes larger and the distribution of particles becomes more uniform; As the sintering temperature increased, the mechanical properties of Cu-Co-based alloy matrix enhanced.

Fabrication of (Cemented Carbides/Steel) Bilayered Materials by Powder Metallurgy

2009 ◽  
Vol 631-632 ◽  
pp. 239-244 ◽  
Author(s):  
Aurelie Thomazic ◽  
Celine Pascal ◽  
Jean Marc Chaix
Keyword(s):  
Powder Metallurgy ◽  
Design Of Experiments ◽  
Heating Rate ◽  
Sintering Temperature ◽  
Compaction Pressure ◽  
Material Design ◽  
Cemented Carbides ◽  
Interface Quality ◽  
Carbide Steel ◽  
Steel Material

This paper analyses the effects of five parameters (composition, compaction pressure, heating rate, sintering temperature and duration) on the sintering of a bilayered (cemented carbide/steel) material. Design of experiments is used to reduce the number of experiments and to analyse the results. After sintering, each sample is characterized (difference of shrinkage, shrinkage anisotropy, density and microstructure). Composition, sintering temperature and duration are the three main parameters which control the sintering of bimaterials, their microstructure and the interface quality. The heating rate and the compaction pressure have no significant effect in the tested domain.

scholarly journals The use of flat-ended projectiles for determining dynamic yield stress - II. Tests on various metallic materials

1948 ◽  
Vol 194 (1038) ◽  
pp. 300-322 ◽  
Keyword(s):  
Yield Strength ◽  
Dynamic Strength ◽  
Soft Materials ◽  
Static Strength ◽  
Compressive Yield Strength ◽  
Dynamic Tests ◽  
Pure Lead ◽  
Permanent Strain ◽  
Yield Values ◽  
Static Conditions

A description is given of the experimental technique devised to apply the method outlined theoretically in part I to the measurement of the dynamic compressive yield strength of various steels, duralumin, copper, lead, iron and silver. A polished piece of armour steel was employed as a target, and cylindrical specimens were fired at it at various measured velocities from Service weapons. The distance between the weapon and target was made short to ensure normal impact, and apparatus was devised for the precise measurement of striking velocity over this short range. The dynamic compressive yield strength was computed from the density of the specimen, the striking velocity, and from measurements of the dimensions of the test piece before and after test. Details are given of the accuracy of the various measurements, and of their effect on the values of yield strength. The method was found to be inaccurate at low and high velocities. For instance, with mild steel, satisfactory results were only obtainable within the range 400 to 2500 ft. /sec. The range of velocities within which satisfactory results could be obtained varied with the quality of the material tested, soft metals giving results within a much lower range than that necessary for harder materials. Because of its failure at low velocities, the method could not be employed to bridge the gap between static and dynamic tests. The rate of strain employed in the dynamic tests could not be measured, but was estimated to be of the order of 10,000 in. /in. /sec. With the materials tested little change of dynamic strength occurred within the range of striking velocities employed, probably because the rate of strain did not vary to any great extent with the striking velocity. Within the range of weapons available, that is, from a 0·303 in. rifle up to a 13 pdr. gun (calibre 3·12 in.), little change of dynamic strength occurred with alteration of the initial dimensions of the specimens, probably because the corresponding change of rate of strain was not large. In general, the dynamic compressive yield strength S was greater than the static strength Y represented by the compressive stress giving 0·2% permanent strain. For steels of various types, regardless of chemical composition and heat treatment, there was a relation between S / Y and the static strength Y , the ratio decreasing from approximately 3 when Y was 20 tons/sq. in. to 1 when Y was 120 tons/sq. in. A similar relation occurred with duralumin, S / Y varying from 2·5 at Y = 8 tons/sq. in. to 1·4 at Y = 25 tons/sq. in. Dynamic compressive yield values were obtained for soft materials such as pure lead, copper and Armco iron, which, under static conditions, gave no definite yield values. A plot of the unstrained length of the specimen X , expressed as X / L (where L = initial overall length), versus the final overall length L 1 , expressed as L 1 / L , was made for the various materials. Any specified value of X / L was associated with greater values of L 1 / L for the more ductile materials, such as copper and lead, than for the brittle materials, such as armour plate and duralumin.

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