scholarly journals Synthesis and Characterization of Stainless Steel Foam Via Powder Metallurgy Taking Acicular Urea As Space Holder

2015 ◽  
Vol 12 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Shailendra Joshi ◽  
Gaurav Gupta ◽  
Mohit Sharma ◽  
Amit Telang ◽  
Taru Mahra
Keyword(s):  
Stainless Steel ◽  
Powder Metallurgy ◽  
High Strength ◽  
Strain Diagram ◽  
High Porosity ◽  
Aluminum Foams ◽  
Plateau Stress ◽  
Space Holder ◽  
Sem Micrograph ◽  
Energy Absorbing

Stainless steel foams are produced via powder metallurgy process taking acicular urea as space holder contributing porosity with 40-70 volume %. The resulting changes in microstructure of compact after each operation comprising cold compaction, pre-heating and sintering are discussed along with causes with the help of SEM micrograph. The processed foam samples using 40 % urea by volume are quite regular and acicular in shape but with increase in porosity regularity starts diminishing. It is observed that the foam samples with 40 % porosity doesn’t show any plateau stress as in aluminum foams but those with 50 % porosity (approximately 80 MPa maximum plateau stress) and 60 % porosity (approx.45MPa) shows plateau region in true stress-strain diagram during compression test due before final densification process. It is observed that with increasing porosity plateau stress decreases, since lesser force is required to densify the foam. Therefore the stainless steel foams with low porosity can be used in light weight high strength applications e.g. structures whereas with high porosity have impact energy absorbing applications e.g. damping elements in buildings or vehicles, etc.

scholarly journals Comparative analysis of characteristics of stainless steel cellular material prepared through powder metallurgy using accicular and crushed urea as spaceholder

2019 ◽  
Vol 16 (2) ◽  
pp. 183-188
Author(s):  
Shailendra Joshi
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Powder Metallurgy ◽  
High Strength ◽  
Metallic Foam ◽  
Space Holder ◽  
Excellent Mechanical Property ◽  
Circular Holes ◽  
Steel Foam ◽  
Damping Capability

Stainless steel has an excellent mechanical property as well as high corrosion resistance. Stainless steel foams, therefore, seemed like an attractive material for impact energy absorption applications where damping capability is required such as in vehicles and buildings. Also when stainless steel foam is produced as stainless steel foam, the material density will be reduced thus the resulting foam will be a combination of light weight and high strength that can also be used in high strength applications. In our analysis, we tried to produce stainless steel foam through powder metallurgy in order to control mechanical properties in a better manner compared to the casting method. Also, we try to compare the pore morphology in foams on changing the space holder from accicular urea to crushed urea using FE-SEM. The properties of stainless steel foam, to a large extent, are found to depend on the arrangement of the pores which is decided by the space holder utilized during its synthesis using powder metallurgy route. The stainless steel obtained using acicular carbamide as space holder is found to possess acicular or irregular pores whereas those produced with crushed urea as space holder possesses nearly circular holes. Also, the previous foams are found to have better mechanical properties contributing towards more useful metallic foam.

Properties of Precipitation Hardening 17-4 PH Stainless Steel Manufactured by Powder Metallurgy Technology

2013 ◽  
Vol 811 ◽  
pp. 87-92 ◽  
Author(s):  
Jan Kazior ◽  
Aneta Szewczyk-Nykiel ◽  
Tadeusz Pieczonka ◽  
Marek Hebda ◽  
Marek Nykiel
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Powder Metallurgy ◽  
Ferritic Stainless Steel ◽  
Process Parameters ◽  
Stainless Steels ◽  
Precipitation Hardening ◽  
High Strength ◽  
Martensitic Stainless Steels ◽  
Heat Treated

Alloys from austenitic and ferritic stainless steel found to be satisfactory for a great many applications. However, for applications that require higher levels of strength and hardness from the martensitic grades are frequently specified. Martensitic stainless steels offer significantly higher strengths but have to low ductility. For this reason for application where high levels of strength and a moderate ductility is required, the precipitation strengthened stainless steels are often considered. One of the most popular alloy of this kind of stainless steel is 17-4 PH. The aim of the present paper was to examined the influence the process parameters in conventional powder metallurgy processing on the mechanical properties of the 17-4 PH alloy in both as-sintered and heat treated conditions. In was found that temperature of aged is a very sensitive parameter for obtained high strength and acceptable ductility.

The Effect of Different Composition of Stainless Steel (SS316L) Foam via Space Holder Method

2016 ◽  
Vol 1133 ◽  
pp. 310-313 ◽  
Author(s):  
Murni Faridah Mahammad Rafter ◽  
Sufizar Ahmad ◽  
Rosdi Ibrahim
Keyword(s):  
Stainless Steel ◽  
Powder Metallurgy ◽  
Sintering Process ◽  
Wear Performance ◽  
Space Holder ◽  
Powder Metallurgy Process ◽  
Lower Porosity ◽  
Steel Foam ◽  
Cold Pressed ◽  
Metallurgy Process

Stainless Steel materials (SS316L) generally known as a highly wear performance and resistant to corrosion. The purpose in this study is to produce the stainless steel foam and physical properties of sintered 316L stainless steel materials produced by powder metallurgy (P/M) method. In this paper, the method is based on using spherical urea as space holder was investigated. Then, the foams will be given to consider the properties of SS316L foam after sintering process. Powder metallurgy process needs to go through the mixing, pressing, sintering and analysis. The selected compositions of SS316L were varied from 50 wt % to 60 wt % SS316L, respectively while the remaining percentages are foaming agent. The SS316L powders were cold-pressed with 8 tons pressure and sintered at 1200°C via tube furnace. The SS316L foams were then characterised using Scanning Electron Microscopy (SEM) for morphological characterisation of the samples after sintering process. Lastly, porosity and density were tested for this sample. As a result, the composition with 60 wt % SS316L is provided higher bulk density and lower porosity which are 4.34 g/cm3 and 69.03 %, respectively.

Stainless steel foams made through powder metallurgy route using NH4HCO3 as space holder

2015 ◽  
Vol 88 ◽  
pp. 430-437 ◽  
Author(s):  
D.P. Mondal ◽  
Hemant Jain ◽  
S. Das ◽  
A.K. Jha
Keyword(s):  
Stainless Steel ◽  
Powder Metallurgy ◽  
Space Holder ◽  
Powder Metallurgy Route

scholarly journals Sustainable Production of Powder Metallurgy Aluminum Foams Sintered by Concentrated Solar Energy

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1544
Author(s):  
Antonio Cañadilla ◽  
Ana Romero ◽  
Gloria P. Rodríguez
Keyword(s):  
Compressive Strength ◽  
Powder Metallurgy ◽  
Solar Energy ◽  
Energy Absorption ◽  
Impact Energy ◽  
Low Cost ◽  
Powder Metallurgy Method ◽  
Aluminum Foams ◽  
Space Holder ◽  
Concentrated Solar Energy

Porous aluminum foams were successfully fabricated following the space-holder powder metallurgy method with a solar sintering stage. Al foams with porosities of 50, 60, and 70 vol.% were sintered in a low-cost Fresnel lens. Green parts were prepared using aluminum powder as the main metallic material and saccharose as a soluble space-holder. The dissolution stage was designed for each foam and required longer periods of time, between 8 and 32 h, as the design porosity increased. Brown parts were fully sintered by concentrated solar energy at a lower temperature (500 °C) and for shorter times (12–20 min) than those required by conventional sintering techniques (640 °C, ~9 h). The evaluation of density and the characterization of pore size and distribution in the sintered foams was carried out. All obtained foams were stable and presented a homogeneously distributed porosity, very close to the design porosity, with differences lower than 2.1 vol.%, and with approximately half being characterized as open porosity. Moreover, the solar sintered foams presented a high quality, and similar or even greater mechanical properties (such as compressive strength and impact energy absorption) than those achieved by conventional techniques. Foams with 50 vol.% of porosity exhibited the best mechanical behavior, in terms of impact-energy absorption (24.42 MJ/m3) and compressive strength (27.4 MPa).

scholarly journals Production of Porous Stainless Steel using the Space Holder Method

2021 ◽  
Vol 50 (2) ◽  
pp. 507-514
Author(s):  
Koon Tatt Tan ◽  
Norhamidi Muhamad ◽  
Andanastuti Muchtar ◽  
Abu Bakar Sulong ◽  
Yih Shia Kok
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Elastic Modulus ◽  
Powder Metallurgy ◽  
Yield Strength ◽  
Sintering Temperature ◽  
Volumetric Shrinkage ◽  
Metallic Foams ◽  
Space Holder ◽  
Porous Stainless Steel

Metallic foams and porous materials can be produced by various methods. Among the methods that can produce metallic foams and porous materials, powder metallurgy is a promising method. This study investigates the production of a porous stainless steel by the space holder method in powder metallurgy. A novel space holder i.e. glycine and binder consisting of polymethylmethacrylate and stearic acid are used. Different amounts of glycine are added to the mixture of stainless-steel powder and binder. Subsequently, each mixture is cold-pressed at a pressure of 9-ton m-2. The samples are sintered at 1050 and 1150 °C with holding times of 30, 60, and 90 min. The microstructures and physical and mechanical properties of the sintered samples are investigated. A porous stainless steel with porosity ranging from 30.8 to 51.4% is successfully fabricated. Results show that the glycine content and sintering parameters influence the properties of the porous stainless steel. The sintering temperature significantly affects volumetric shrinkage. Volumetric shrinkage decreases as the volume fraction of glycine increases to 30% whereas sintering temperature 1150 °C and holding time 90 min will increase the volumetric shrinkage. The compressive yield strength and corresponding elastic modulus are in the ranges of 22.9 to 57.6 MPa and 6.3 to 26.8 GPa, respectively. The samples produced have potential biomedical applications because their mechanical properties, yield strength and elastic modulus match those of human bones.

scholarly journals Binder Jetting Additive Manufacturing of High Porosity 316L Stainless Steel Metal Foams

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3744
Author(s):  
Ganesh Kumar Meenashisundaram ◽  
Zhengkai Xu ◽  
Mui Ling Sharon Nai ◽  
Shenglu Lu ◽  
Jyi Sheuan Ten ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Young’S Modulus ◽  
316L Stainless Steel ◽  
Young's Modulus ◽  
Linear Shrinkage ◽  
High Porosity ◽  
Processing Conditions ◽  
Space Holder ◽  
Compression Properties ◽  
Binder Jetting

High porosity (40% to 60%) 316L stainless steel containing well-interconnected open-cell porous structures with pore openness index of 0.87 to 1 were successfully fabricated by binder jetting and subsequent sintering processes coupled with a powder space holder technique. Mono-sized (30 µm) and 30% (by volume) spherically shaped poly(methyl methacrylate) (PMMA) powder was used as the space holder material. The effects of processing conditions such as: (1) binder saturation rates (55%, 100% and 150%), and (2) isothermal sintering temperatures (1000 ○C to 1200 ○C) on the porosity of 316L stainless steel parts were studied. By varying the processing conditions, porosity of 40% to 45% were achieved. To further increase the porosity values of 316L stainless steel parts, 30 vol. % (or 6 wt. %) of PMMA space holder particles were added to the 3D printing feedstock and porosity values of 57% to 61% were achieved. Mercury porosimetry results indicated pore sizes less than 40 µm for all the binder jetting processed 316L stainless steel parts. Anisotropy in linear shrinkage after the sintering process was observed for the SS316L parts with the largest linear shrinkage in the Z direction. The Young’s modulus and compression properties of 316L stainless steel parts decreased with increasing porosity and low Young’s modulus values in the range of 2 GPa to 29 GPa were able to be achieved. The parts fabricated by using pure 316L stainless steel feedstock sintered at 1200 ○C with porosity of ~40% exhibited the maximum overall compressive properties with 0.2% compressive yield strength of 52.7 MPa, ultimate compressive strength of 520 MPa, fracture strain of 36.4%, and energy absorption of 116.7 MJ/m3, respectively. The Young’s modulus and compression properties of the binder jetting processed 316L stainless steel parts were found to be on par with that of the conventionally processed porous 316L stainless steel parts and even surpassed those having similar porosities, and matched to that of the cancellous bone types.

Microstructure and Compression Behavior of Cenosphere Filled Aluminum Syntactic Foams

2012 ◽  
Vol 706-709 ◽  
pp. 704-708
Author(s):  
Qiang Zhang ◽  
Gao Hui Wu
Keyword(s):  
Fly Ash ◽  
Pure Aluminum ◽  
Aluminum Matrix ◽  
High Strength ◽  
Syntactic Foams ◽  
Compression Tests ◽  
Aluminum Foams ◽  
Compression Behavior ◽  
Plateau Stress ◽  
X Ray

Aluminum syntactic foams were fabricated by pressure-infiltrating liquid pure aluminum into packed preforms of cenosphere fly ash. The morphology, true density and porosity of fly ash microballoons were characterized. The microstructure of the syntactic foams demonstrated uniform distribution of the microballoons in the aluminum matrix and seldom infiltration of cenosphere fly ash. These foams were subjected to quasi-static uniaxial compression tests and behaved like high strength aluminum foams under compressive deformation, exhibiting an extended plateau region in the stress–strain curves. With the decreasing of fly ash diameter, the plateau stress and absorbed energy of the syntactic foams increased. X-ray microcomputed tomography was used to examine the foam microstructures after interrupted compression and reveal the damage evolution. The current work provides a better understanding on the structure and mechanical properties of aluminum matrix syntactic foams.

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