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1

Assessment of High-Temperature Oxidation Properties of 316L Stainless Steel Powder and Sintered Porous Supports for Potential Solid Oxide Cells Applications

Kabir Ahsanul, Koszelow Damian, Miruszewski Tadeusz, Tinti Victor Buratto, Kern Frank, Molin Sebastian

Advances in Science and Technology. Research Journal

|

2024

|

Vol. 18, no 5

EN

In this work, oxidation properties of austenitic 316L stainless steel powder and sintered porous support were investigated at the temperature range of ~600-750 °C for 100 hours in ambient air. Oxidation kinetics was determined by continuous thermogravimetry and analyzed employing parabolic rate law. It was observed that oxidation leads to the formation of an oxide scale, with substantial oxidation occurring at ≥ 650 °C in the powder. The porous steel support was fabricated by tape casting method with two distinct pore former concentrations. The microstructural features of both the powder and support were investigated by X-ray diffractometry and scanning electron microscopy coupled with energy-dispersive X-ray analysis. The mechanical properties of the metal support were examined before and after oxidation via a microhardness test. The effect of porosity on the resulting properties of the metal support was also highlighted. In summary, 316L stainless steel support suits SOCs applications below 600 °C.

2

Size‑dependent constitutive model incorporating grain refinement and martensitic transformation

Liu Shengqiang, Li Wei, Shen Jinxia, Yang Xiaoming, Wang Baoyu, Liu Jinping

Archives of Civil and Mechanical Engineering

|

2023

|

Vol. 23, no. 1

art. no. e38, 2023

EN

The deformation behaviour of materials at the micro-scale level is different from that at the macro-scale level due to the effect of grain size (GS). The mechanism of the influence on martensitic transformation by GS is still unclear, and there are relatively few studies on the relationship between grain refinement and martensitic transformation, most of which focus on the relationship between the initial GS of the material and martensitic transformation. Therefore, in this study, the interaction between grain refinement and martensitic transformation was investigated using a dislocation density-based multiscale constitutive model that incorporated dislocation sliding, strain-induced martensitic transformation (SIMT) related to grain size, and grain refinement. The proposed model evaluated the GS-dependent deformation behaviour of 316L stainless steel (SS). Subsequently, a genetic algorithm was used to determine the parameters of the established model, and the calculated results were compared with that of the experimental data to verify the accuracy of the model. The developed multiscale constitutive model was implemented in Abaqus user subroutine to further investigate the deformation mechanism and validate its accuracy. The results demonstrated that the GS had a significant effect on the SIMT, with the volume fraction of martensite increasing with a rise in the initial austenite GS. In addition, grain refinement affected SIMT and the growth rate of martensite content decreased with the grain refinement caused by deformation. The formation of martensite led to grain refinement, with the refined grains producing negative feedback on the SIMT, thus inhibiting the occurrence of martensitic transformation. This study revealed the microscopic deformation mechanism of 316L SS and provided a constitutive model for micro-forming.

3

Empirical Study on the Effect of Tungsten Carbide Grain Size on Wear Resistance, Cutting Temperature, Cutting Forces and Surface Finish in the Milling Process of 316L Stainless Steel

Franczyk Emilia, Małek Marcin

Advances in Science and Technology. Research Journal

|

2023

|

Vol. 17, no 6

367--377

EN

Cutting tools made of the WC-Co sintered carbides are now very popular and are widely used in machining of materials. However, there are numerous problems in this area which require more research and need to be studied further. This paper presents the results of an experimental study aimed at discovering the impact of the microstructure, particularly of the tool substrate grain size, on the quality of the machined surface, cutting forces and temperature in the cutting zone, as well as the tool life. In addition, the impact of the feed was considered. The machining process involved side milling of a cuboidal block made of the AISI 316L steel which, due to its specific properties, is widely used in many industries. The tools used in the tests had different WC phase grain size: 0.18, 0.28 and 0.31 μm, respectively, and moreover the middle specimen had also a non-homogeneous structure and an increased content of the Co matrix. The tests proved a significant impact of the tool microstructure on the tool life and the roughness parameters Ra and Rz of the machined surface. The impact of the studied factors on the forces and the temperature in the cutting zone was not as strong, because it did not exceed 20%. The value and the novel character of the paper results from the fact that it concerns a specific case: side milling of the 316L steel with the use of the WC-Co sintered carbide tools, and consequently provides a contribution to solve a practical industrial issue.

4

The influence of plasma-sprayed coatings on surface properties and corrosion resistance of 316L stainless steel for possible implant application

Woźniak Anna, Staszuk Marcin, Reimann Łukasz, Bialas Oktawian, Brytan Zbigniew, Voinarovych Sergii, Kyslytsia Oleksandr, Kaliuzhnyi Sergii, Basiaga Marcin, Adamiak Marcin

Archives of Civil and Mechanical Engineering

|

2021

|

Vol. 21, no. 4

223--243

EN

Herein, we analyzed the morphology of atmospheric plasma-sprayed (APS) coating on medical 316L stainless steel and its influence on the physical and electrochemical properties of implant application. Five types of coatings were examined: hydroxyapatite (HAp), titanium (Ti), zirconium (Zr), Ti/HAp and Zr/HAp. The base properties of the coatings were analyzed via chemical and phase composition, surface topography, surface wettability and in particular the corrosion resistance in Ringer solution in immersed conditions and potentiodynamic test, and EIS analysis. APS coating of pure HAp on 316L stainless steel showed poor cohesive bonding to the substrate material, whereas the application of Ti and Zr interlayer prior to HAp deposition improved surface morphology and coating properties. The beneficial effect of Ti and Zr interlayer under HAp layer on binding was demonstrated. HAp containing coatings (HAp, Ti/HAp and Zr/HAp) show Ca/P ratio greater than 1.8, which may positively influence the differentiation of osteogenic cells and good adhesion to bones. Among the studied materials, the composite coatings with Zr or Zr/HAp showed favorable physicochemical properties and the highest corrosion resistance in Ringer solution.

5

The Influence of the Process Parameters on the Microstructure and Properties SLM Processed 316L Stainless Steel

Woźniak A., Adamiak M., Chladek G., Kasperski J.

Archives of Metallurgy and Materials

|

2020

|

Vol. 65, iss. 1

73--80

EN

Selective Laser Melting (SLM) is a modern manufacturing method with many applications in medicine, aerospace and auto-motive industries. SLM processed materials are characterized by good dimensional accuracy and properties comparable or superior to materials obtained by traditional processing methods. In this paper an SLM process was used to obtain 316L stainless steel parts. This paper presents the microstructure, chemical and phase composition, physicochemical and electrochemical properties of 12 groups of tested samples, differentiated by the SLM processing parameters. Based on the investigation, it can be inferred that the selection of the appropriate SLM parameters is very important to determined final material properties. The samples producedwith the energy density E = 600 J/mm3 were observed to possess optimum properties - a homogeneous structure, density closest to the desired one, good wettability and pitting corrosion resistance.

6

Novel SiC Dispersion Strengthened Austenitic Steels Prepared by Powder Technology

Ben Zine Haroune Rachid, Sahin Filiz Cinar, Czigány Zsolt, Balázsi Katalin, Balázsi Csaba

Archives of Metallurgy and Materials

|

2019

|

Vol. 64, iss. 4

1519--1526

EN

In this work, the 316L austenitic steel based milled and sintered composites with 0.33 wt% and 1 wt% SiC ultra-fine particles addition have been prepared. The high efficient attrition milling provided an efficient size reduction of the 316L steel grains and homogeneous distribution of the SiC nanoparticles before sintering process. Spark plasma sintering (SPS) was used for compaction of milled powder mixtures. The effect of SiC addition on the milling efficiency and the structure of the composites have been studied. It was found that the amount of ceramic addition did not influence the efficiency of milling process, powder mixtures with flake like grains have been obtained. On the other hand, the intensive milling assured an optimal coverage of 316L stainless steel grains with submicron sized ceramic particles in both cases. The sintered composites showed high densities with the presence of small amount of closed porosities. Structural, mechanical and tribological examinations of 316L/SiC composites have been performed and presented.

7

Geometrical structure of surface after turning of 316L stainless steel in laser assisted conditions

Szymański Michał, Kukliński Mateusz

Archives of Mechanical Technology and Materials

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2019

|

Vol. 39

66--73

EN

The effects of turning 316L steel in a laser assisted machining are presented in this paper. The properties of 316L stainless steel are also shown in this article. In order to show correlation between the technological parameters, microgeometry of cutting tools and geometrical structure of surface, turning of material in grade 316L supported by laser has been executed. In addition, optical examination of cutting inserts has been performed and geometrical measurements of machined surfaces have been taken. The results of researches on the effects of the technological parameters and cutting tool's microgeometry on the geometrical structure of the 316L steel surface after turning in LAM conditions are described.

8

Effect of shot peening on microstructure, hardness, and corrosion resistance of AISI 316L

Iswanto P. T., Akhyar H., Faqihudin A.

Journal of Achievements in Materials and Manufacturing Engineering

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2018

|

Vol. 89, nr 1

19--26

EN

Purpose: This research conducted to analyse the effect of shot peening on surface structure, hardness, and resistance to corrosion of AISI 316L. Design/methodology/approach: The shot peening process is carried out on the surface of 316L stainless steel samples with four peening durations, and they are 2, 4, 15, and 30 minutes. Shot ball steel with diameter 0.4 mm for metal shot blasting and model S110 of ISO 11124/3 and SAEJ827, with the chemical composition, are C (0.8-1.2 wt.%), Mn (0.6-1.2 wt.%), Si (min. 0.4 wt.%), S (max. 0.05 wt.%), P (max. 0.05 wt.%), with a hardness of steelball, about 40-50 HRC. The pressure of compressor kept constant at 8 bar with a diameter of the nozzle is 5 mm, and the distance between the nozzle and the sample surface variated by 6 cm and 12 cm for each shooting duration. Findings: The result shows that the shot peening increases the surface hardness of the material, changes the microstructure on the surface layer and increases the resistance to corrosion. Shot peening with 30 minutes of shooting duration and 6 cm of shooting distance can improve the metal surface properties, which has a surface hardness of 772.23 HV and good on corrosion resistance. Research limitations/implications: The results of this experiment show that shot peening distance of 6 cm for 30 minutes achieved the highest surface hardness of AISI 316L. The corrosion rate decline with increasing duration and nearer distance of shooting balls. Practical implications: In the development of the implant material, AISI 316L need to be improved, its material properties, so it can be used safely and compatibly. Shot peening is a cold working process of metal to increase the material properties by shooting the steel ball into the surface of a material. Originality/value: Based on the experimental results it was obtained that variations shot peening distance and shot peening duration can change grain morphologies, subsequently affect hardness and corrosion resistance on AISI 316L.

9

Analiza możliwości poprawy struktury stereometrycznej powierzchni elementów wykonanych w technologii DMLS

Palczak A.

Problemy Nauk Stosowanych

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2016

|

T. 5

85--92

PL

Wstęp i cel: W artykule dokonano analizy struktury stereometrycznej powierzchni i opisano podjęte próby poprawy jej właściwości dla elementów wykonanych metodą wytwarzania przyrostowego. Materiał i metody: Przebadano strukturę stereometryczną powierzchni elementów wytworzonych poprzez selektywne spiekanie wiązką lasera sproszkowanej stali 316L. Podjęto również próbę poprawy parametrów powierzchni wytworzonych elementów poprzez obróbkę skrawaniem, szlifowanie, nagniatanie ślizgowe i toczne. Wyniki: W wyniku przeprowadzonych badań uzyskano znaczą poprawę parametrów względem powierzchni surowych, uzyskanych bezpośrednio w procesie wytwarzania przyrostowego. Jednocześnie parametry powierzchni uzyskanych konwencjonalnymi metodami nie różniły się w znaczący sposób. Wniosek: Warstwa wierzchnia elementów wykonanych metodą laserowego spiekania proszków metali cechuje się znaczną chropowatością. Dodatkowa obróbka tak wytworzonych detali poprzez zastosowanie konwencjonalnych metod takich jak skrawanie lub nagniatanie pozwala w istotny sposób zmniejszyć chropowatość.

EN

Introduction and aim: The article shows the analyze of the surface texture and describes attempts to improve surface parameters for the components made with the use of additive manufacturing technology. Material and methods: The surface texture of the elements made of powdered 316L stainless steel with the use of direct metal laser sintering technology were studied. Also an attempt was made to improve the parameters of the surface of those elements by machining or grinding and after that by roller or slide burnishing. Results: During the studies a significant improvement was achieved, relative to the surface parameters obtained directly in the DMLS process. Surface parameters obtained by conventional methods did not differ significantly. Conclusion: The outer layer of elements made out of metal powders with the laser sintering technology is characterized by a high roughness. Additional mechanical treatment of these parts with the use of conventional methods like turning or grinding and than roller or slide burnishing can significantly reduce the roughness.

10

Towards processing of multilayered metallic materials : constrained compression testing

Bajda S., Krzyzanowski M., Kwiecień M., Majta J., Lisiecki Ł., Sroka J.

Computer Methods in Materials Science

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2016

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Vol. 16, No. 2

76--86

EN

The complex analysis of the interface behaviour has been performed during constrained compression testing of 316L steel plates as a way towards processing of the multilayered metallic materials. The approach is based on a combination of experiments under appropriate operating conditions and computer modelling based on finite element (FE) methodology for interpretation of the test results. Multilayered metallic structure was successfully obtained using the applied constrained compression testing technique. The specially designed die and compression specimens allowed for joining of the steel plates together even at room temperatures. The performed numerical analysis using the ABAQUS/Standard FE software revealed the strain and stress localisation areas within the multilayered structure among other features that are described in the paper. The results are in agreement with experimental observations.

PL

Przeprowadzono kompleksową analizę ewolucji naprężeń i odkształceń w pobliżu granic rozdziału podczas ograniczonego ściskania płytek ze stali 3I6L w celu opracowania procesów wytwarzania wielowarstwowych materiałów metalicznych, w tym o budowie nanostrukturalnej. Przeprowadzone badania są oparte na połączeniu badań doświadczalnych w odpowiednich warunkach / modelowaniem komputerowym opartym o metodę elementów skończonych (MES) w celu interpretacji wykonywanych prób. Przeprowadzone badania pozwoliły na uzyskanie wielowarstwowej struktury metalicznej obserwowanej w przekroju poprzecznym próbek poddanych ograniczonemu ściskaniu. Specjalnie zaprojektowana matryca oraz próbki do ściskania pozwoliły na połączenie stalowych płytek nawet w temperaturze pokojowej. Przeprowadzona analiza numeryczna z wykorzystaniem oprogramowania ABAQUS/Standard ujawniła obszary lokalizacji naprężeń i odkształceń wewnątrz wielowarstwowej struktury, a także inne elementy, które zostały opisane w pracy. Wyniki analizy numerycznej są zgodne z wynikami badań doświadczalnych.

11

Wpływ temperatury spiekania na zużycie tribologiczne spieków 316L i 316L-HAp otrzymanych metodą iskrowego spiekania plazmowego

Mróz A., Garbiec D., Wiśniewski T., Gierzyńska-Dolna M., Magda J.

Tribologia

|

2015

|

nr 2

75--86

PL

Stosowanie bezniklowej stali austenitycznej 316L na implanty układu kostno-stawowego wiąże się z wieloma problemami eksploatacyjnymi. Jednym ze sposobów radzenia sobie z tymi ograniczeniami może być opracowanie nowych materiałów, w tym kompozytów, z zastosowaniem metalurgii proszków. W artykule przedstawiono wyniki badań tribologicznych spieków 316L i 316LHAp (hydroksyapatyt, HAp) otrzymanych metodą iskrowego spiekania plazmowego z zastosowaniem różnej temperatury spiekania. Dla stali 316L zwiększenie temperatury spiekania z 1000 do 1100°C skutkowało pogorszeniem odporności na zużycie. Niemniej w porównaniu z litą stalą 316L odporność na zużycie tych materiałów była znacząco większa. Dla kompozytów 316L-HAp zwiększenie temperatury spiekania skutkowało polepszeniem odporności na zużycie. Zużycie kompozytu spiekanego w niższej temperaturze było porównywalne ze zużyciem materiału referencyjnego.

EN

The use of 316L stainless steel in osteoarticular system implants is associated with many operational problems. One of the methods that deal with these restrictions may be the development of new materials, including composites, using powder metallurgy. This paper presents the results obtained during tribological tests of 316L and 316L-HAp sintered materials produced with the use of the spark plasma sintering method applying various sintering temperature. The increase of the sintering temperature from 1000 to 1100°C resulted in the deterioration of the wear resistance of 316L. However, compared to solid 316L, the wear resistance of these materials was several dozen times higher. The increase of the sintering temperature resulted in the improvement of the wear resistance of 316L-HAp. The wear resistance of the composites that had been sintered at lower temperatures was comparable to the reference material.

12

Oxide Formation In Metal Injection Molding Of 316L Stainless Steel

Jang J. M., Lee W., Ko S.-H., Han C., Choi H.

Archives of Metallurgy and Materials

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2015

|

Vol. 60, iss. 2B

1281--1285

EN

The effects of sintering condition and powder size on the microstructure of MIMed parts were investigated using water-atomized 316L stainless steel powder. The 316L stainless steel feedstock was injected into micro mold with micro features of various shapes and dimensions. The green parts were debound and pre-sintered at 800°C in hydrogen atmosphere and then sintered at 1300°C and 1350°C in argon atmosphere of 5torr and 760torr, respectively. The oxide particles were formed and distributed homogeneously inside the sample except for the outermost region regardless of sintering condition and powder size. The width of layer without oxide particles are increased with decrease of sintering atmosphere pressure and powder size. The fine oxides act as the obstacle on grain growth and the high sintering temperature causes severe grain growth in micro features due to larger amount of heat gain than that in macro ones.

13

Double Step Sintering Behavior Of 316L Nanoparticle Dispersed Micro-Sphere Powder

Jeon B., Sohn S. H., Lee W., Han C., Kim Y. D., Choi H.

Archives of Metallurgy and Materials

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2015

|

Vol. 60, iss. 2B

1155--1158

EN

316L stainless steel is a well-established engineering material and lots of components are fabricated by either ingot metallurgy or powder metallurgy. From the viewpoints of material properties and process versatility, powder metallurgy has been widely applied in industries. Generally, stainless steel powders are prepared by atomization processes and powder characteristics, compaction ability, and sinterability are quite different according to the powder preparation process. In the present study, a nanoparticle dispersed micro-sphere powder is synthesized by pulse wire explosion of 316L stainless steel wire in order to facilitate compaction ability and sintering ability. Nanoparticles which are deposited on the surface of micro-powder are advantageous for a rigid die compaction while spherical micro-powder is not to be compacted. Additionally, double step sintering behavior is observed for the powder in the dilatometry of cylindrical compact body. Earlier shrinkage peak comes from the sintering of nanoparticle and later one results from the micro-powder sintering. Microstructure as well as phase composition of the sintered body is investigated.

14

Application of X-ray CT method for discontinuity and porosity detection in 316L stainless steel parts produced with SLM technology

Ziółkowski G., Chlebus E., Szymczyk P., Kurzac J.

Archives of Civil and Mechanical Engineering

|

2014

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Vol. 14, no. 4

608--614

EN

Industrial tomography (XCT) is a nondestructive test method that provides information about spatial distribution of X-ray absorption in the analyzed structures. The aim of this paper was to examine the possibility and accuracy of application of XCT method for discontinuity and porosity detection in parts made of 316L stainless steel powder produced by Selective Laser Melting technology. Analysis conducted on three produced test samples showed that the application of XCT as a method of quality control of specimens produced with an additive manufacturing technology offers a wide range of possibilities to detect porosity within materials. Parameters such as the amount of porosity, pore size and pore shape are presented. Accuracy of XCT method strongly depends on the size of the samples analyzed, but the possibility of obtaining information in 3D nondestructively shows considerable advantages of XCT method over traditional metallographic cross-sectional analysis.

15

Inhibition of corrosion of AISI 316L steel in concentrated acetic acid containing NaCl additions

Bala H., Adamczyk L., Owczarek E., Gruetzner T., Seyfang B. C.

Ochrona przed Korozją

|

2012

|

nr 11

460-463

EN

The effect of Akolidine-10 additions (0.001-0.1%) into deaerated, 5M acetic acid solution on corrosion behaviour of 316L (X2CrNiMo 18-14-3) stainless steel has been investigated in the absence and in presence of NaCl addition. It can be postulated that Akolidine-10 decreases the hydrogen activity on the steel corroding surface. Additions of Akolidine-10 into the test solution is particularly advantageous in passive region because it protects steel surface against local corrosion attack.

PL

Badano wpływ dodatków Akolidyny-10 (0,001-0,1%) do odpowietrzonego roztworu 5M kwasu octowego na zachowanie korozyjne stali kwasoodpornej 316L (X2CrNiMo 18-14-3) w nieobecności - i w obecności dodatków NaCl. Uzyskane wyniki pozwalają przyjąć, że Akolidyna-10 zmniejsza aktywność wodoru na korodującej powierzchni stali. Dodatki Akolidyny-10 do roztworu roboczego są szczególnie korzystne w warunkach pasywacji stali, gdyż chronią jej powierzchnię przed lokalnym atakiem korozyjnym.

16

Characterizations and evaluations on the bonding quality of molybdenum disilicides

Lu L. W., Qin W. G.

Archives of Metallurgy and Materials

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2011

|

Vol. 56, iss. 4

1271-1271

EN

In this study, we proposed a new method using the spark plasma sintering technique to bond ceramics to alloys. MoSi2 and 316L stainless steel were chosen as sample materials and can be welded well with graded interlayers. We found that dense uniformed bondings were achieved because of the comparable coefficient of thermal expansion of the interlayers. Furthermore, such a compatibility between the graded interlayers prevented MoSi2 with low toughness from the occurrence of microcracks resulted from the residual stresses formed during cooling of the bondings.

PL

W pracy zaproponowano nowa metodę łączenia ceramiki i stopów metodą spiekania iskrowo plazmowego SPS (spark plasma sintering). MoSi2 i stal nierdzewna 316L zostały wybrane jako przykładowe materiały i moga byc łaczone poprzez gradientowe warstwy pośrednie. Okazało się, że zwarte, jednorodne połączenia zostały uzyskane dzieki porównywalnemu współczynnikowi rozszerzalności cieplnej warstw pośrednich. Ponadto, tego rodzaju zgodnosc pomiedzy warstwami pośrednimi zapobiegła wystapieniu mikropęknięć w MoSi2, który jest materiałem o niskiej twardości, będacych wynikiem naprezen powstałych podczas chłodzenia połączeń.

17

Analiza procesów zachodzących podczas ściskania porowatej stali 316L do zastosowań biomedycznych

Grądzka-Dahlke M.

Eksploatacja i Niezawodność

|

2010

|

nr 4

16-22

PL

Porowate biomateriały metaliczne są atrakcyjnym materiałem implantacyjnym ze względu na większe od tradycyjnych stopów dopasowanie modułu sprężystości do kości oraz na możliwość przerastania porów tkanką kostną i zapewnienia właściwego mocowania implantu w kości. Materiałom tym stawiane są jednak wysokie wymagania, aby zagwarantować odpowiednią trwałość wszczepu. Wśród tych wymogów są m.in. właściwości mechaniczne, szczególnie wytrzymałość zmęczeniowa, a także właściwości magnetyczne. Wszystkie stosowane obecnie stopy implantacyjne (stale chromowo-niklowe, stopy kobaltu i stopy niklu) są paramagnetykami. Jednak na skutek cyklicznych obciążeń, którym poddawane są implanty podczas eksploatacji w organizmie w niektórych materiałach mogą zajść przemiany strukturalne, zmieniające także właściwości użytkowe biomateriałów. W pracy analizowano zmiany zmęczeniowe, zachodzące pod wpływem obciążeń cyklicznych w porowatych spiekach ze stali 316L, przeznaczonych na implanty biomedyczne oraz ich wpływ na właściwości magnetyczne materiałów. Na podstawie wyników badań można stwierdzić, że spieki porowate wykazują początkowe osłabienie, a następnie stabilizację zmęczeniową w badanym zakresie odkształceń. Badania magnetyczne pokazały, że wraz ze wzrostem stopnia odkształcenia rośnie wartość magnetyzacji spieków ze stali 316L, co może mieć wpływ na właściwości użytkowe tych materiałów.

EN

The porous metallic biomaterials are to be considered very attractive implant materials due to the matching of their elastic modulus to the bone as well as the possibility of bone tissue ingrowth into pores and assurance of good stabilization if implant. High requirements are set though to ensure proper durability. Among these are mechanical properties, especially fatigue strength and magnetic properties. All of recently used implant alloys (Cr-Ni steel, cobalt or titanium alloys) are paramagnetic. However, cyclic stress that implants must stand during exploitation, may cause structural as well as functional changes in biomaterials. In presented work, fatigue changes occurring during cyclic stresses in porous sinters of 316L steel were analyzed, as well as their influence on magnetic properties of investigated materials. The obtained results showed that initial weakening and then fatigue stabilization was observed in the whole range of analyzed strain. The magnetic research indicated magnetization increase as an effect of rising strain. This can affect functional properties of implant materials.

18

Study of hydroxyapatite behaviour during sintering of 316L steel

Szewczyk-Nykiel A., Nykiel M.

Archives of Foundry Engineering

|

2010

|

Vol. 10, iss. 3 spec.

235--240

EN

316L stainless steel – hydroxyapatite composite biomaterials with different hydroxyapatite weight fraction in the composite were investigated. Hydroxyapatite (HAp – Ca10(PO4)6(OH)2) is well known biomaterial. HAp reveals excellent chemical and biological affinity with bony tissues. On the other hand hydroxyapatite shows low mechanical properties. The combination of very good biocompatibility of hydroxyapatite and high mechanical properties of stainless steel seems to be a good solution. In presented research natural origin hydroxyapatite and 316L austenitic stainless steel were used. In this work, metal-ceramics composites were fabricated by the powder metallurgy technology (involving pressing and sintering process). Sintering was carried out at 1250oC in hydrogen atmosphere. The density, porosity and hardness were investigated. Metallographic microscope and SEM were carried out in order to investigate the microstructure. The horizontal NETZSCH DIL 402E dilatometer was used to evaluate the dimensional changes and phenomena occurring during sintering. The research displayed that physical properties of sintered 316L-HAp composites decrease with increase of hydroxyapatite content. Microstructure of investigated composites consists of austenitic and probably inclusions of hydroxyapatite and heterogeneous eutectic occurring on the grain boundaries. It was shown that amount of hydroxyapatite in the powder mixtures influence the dimensional changes occurring during sintering.