Effect of Space Holder on Porosity, Structure and Mechanical Properties of Al Processed via Powder Metallurgy

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.

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Porous Magnesium for Medical Applications - Influence of Powder Size on Mechanical Properties

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.592-593.342 ◽

2013 ◽

Vol 592-593 ◽

pp. 342-345 ◽

Cited By ~ 3

Author(s):

Jaroslav Čapek ◽

Dalibor Vojtěch

Keyword(s):

Mechanical Properties ◽

Powder Metallurgy ◽

Ammonium Bicarbonate ◽

Spherical Particles ◽

Flexural Properties ◽

Medical Applications ◽

Powder Size ◽

Magnesium Powder ◽

Space Holder ◽

Porous Magnesium

Porous magnesium materials appear to be promising candidates for scaffold production. In this work we prepared porous magnesium samples by powder metallurgy using ammonium bicarbonate as space-holder particles. We focused on the influence of the magnesium powder size and shape on product characteristics. Samples prepared using magnesium chips showed significantly worse flexural properties than samples with similar porosities prepared from an equi-axed magnesium powder. Therefore, we can conclude that spherical particles are more suitable for the preparation of porous objects by powder metallurgy.

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Production of Porous Stainless Steel using the Space Holder Method

Sains Malaysiana ◽

10.17576/jsm-2021-5002-21 ◽

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.

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Porous Titanium for Biomedical Applications: Evaluation of the Conventional Powder Metallurgy Frontier and Space-Holder Technique

Applied Sciences ◽

10.3390/app9050982 ◽

2019 ◽

Vol 9 (5) ◽

pp. 982 ◽

Cited By ~ 16

Author(s):

Sheila Lascano ◽

Cristina Arévalo ◽

Isabel Montealegre-Melendez ◽

Sergio Muñoz ◽

José Rodriguez-Ortiz ◽

...

Keyword(s):

Mechanical Properties ◽

Powder Metallurgy ◽

Young’S Modulus ◽

Biomedical Applications ◽

Mechanical Response ◽

Young's Modulus ◽

Pure Titanium ◽

Porous Titanium ◽

Space Holder ◽

Industrial Implementation

Titanium and its alloys are reference materials in biomedical applications because of their desirable properties. However, one of the most important concerns in long-term prostheses is bone resorption as a result of the stress-shielding phenomena. Development of porous titanium for implants with a low Young’s modulus has accomplished increasing scientific and technological attention. The aim of this study is to evaluate the viability, industrial implementation and potential technology transfer of different powder-metallurgy techniques to obtain porous titanium with stiffness values similar to that exhibited by cortical bone. Porous samples of commercial pure titanium grade-4 were obtained by following both conventional powder metallurgy (PM) and space-holder technique. The conventional PM frontier (Loose-Sintering) was evaluated. Additionally, the technical feasibility of two different space holders (NH4HCO3 and NaCl) was investigated. The microstructural and mechanical properties were assessed. Furthermore, the mechanical properties of titanium porous structures with porosities of 40% were studied by Finite Element Method (FEM) and compared with the experimental results. Some important findings are: (i) the optimal parameters for processing routes used to obtain low Young’s modulus values, retaining suitable mechanical strength; (ii) better mechanical response was obtained by using NH4HCO3 as space holder; and (iii) Ti matrix hardening when the interconnected porosity was 36–45% of total porosity. Finally, the advantages and limitations of the PM techniques employed, towards an industrial implementation, were discussed.

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