Microstructure and degradation behavior of forged Fe–Mn–Si alloys

2015 ◽  
Vol 29 (10n11) ◽  
pp. 1540014 ◽  
Author(s):  
Zhigang Xu ◽  
Michael A. Hodgson ◽  
Peng Cao
Keyword(s):  
Hot Forging ◽  
Immersion Test ◽  
General Corrosion ◽  
Degradation Behavior ◽  
Homogenization Treatment ◽  
Arc Melting ◽  
Cast Alloys ◽  
Degradable Biomaterials ◽  
Si Content ◽  
Static Immersion

This work presents a comparative study of a series of Fe – Mn – Si alloys proposed as degradable biomaterials for medical applications. Five Fe -28wt.% Mn -x Si (where x = 0 to 8 wt.%) alloys were fabricated by an arc-melting method. All the as-cast alloys were subsequently subjected to homogenization treatment and hot forging. The microstructure and phase constituents were investigated. It is found that the grain size of the as-forged alloys ranged approximately from 30 to 50 μm. The as-forged Fe – Mn – Si alloys containing Si from 2 to 6 wt.% was comprised of duplex martensitic ε and austenitic γ phases; however, the Si -free and 8 wt.% Si alloys only consisted of a single γ phase. After 30 days of static immersion test in a simulated body fluid (SBF) medium, it is found that pitting and general corrosion occur on the sample surfaces. Potentiodynamic analysis reveals that the degradation rate of the Fe – Mn – Si alloys increased gradually with Si content up to 6 wt.%, beyond which the degradation slows down.

scholarly journals Effect of Structural Modification on Corrosion Behavior of Hypo Eutectic Al-Si Alloy

2018 ◽  
Vol 778 ◽  
pp. 16-21
Author(s):  
Muhammad Mansoor ◽  
Muhammad Kamran Yaseen ◽  
Shaheed Khan
Keyword(s):  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Earth Metal ◽  
Alloy System ◽  
Eutectic Phase ◽  
Al Alloy ◽  
General Corrosion ◽  
Corrosion Properties ◽  
Unmodified Alloy ◽  
Cast Alloys

Al-Si eutectic cast alloys are widely used in aeronautical and automobile industries where significantly high strength, toughness and wear resistance are required. This class of cast alloys exhibit relatively low corrosion resistance in brine environments. The mechanical properties of the alloy system mainly depend upon the shape of Si rich eutectic phase, which mainly has acicular geometry. In present research, the effect of modified microstructure of 12 wt. % Si-Al alloy on corrosion behavior was studied. The needle like Si rich eutectic phase was modified to disperse spherical structure using rare earth metal halides. The corrosion rate and pitting behavior of modified and unmodified alloy were evaluated in 3.5% NaCl solution by general corrosion for calculated time. It was observed that the corrosion rate and pitting tendency of modified alloy had been appreciably reduced as compare to unmodified alloy. The improvement of corrosion properties were the attributes of changed morphology and distribution of Si rich eutectic phase.

Phase Stability and Mechanical Properties of Ti(Ni, Ru) Alloys

2002 ◽  
Vol 753 ◽  
Author(s):  
Masahiro Tsuji ◽  
Hideki Hosoda ◽  
Kenji Wakashima ◽  
Yoko Yamabe-Mitarai
Keyword(s):  
Mechanical Properties ◽  
Phase Transformation ◽  
Phase Stability ◽  
Hot Forging ◽  
Tensile Tests ◽  
Lattice Parameter ◽  
Solid Solution Hardening ◽  
Scanning Calorimetry ◽  
Arc Melting ◽  
Transmission Electron

ABSTRACTEffects of ruthenium (Ru) substitution on constituent phases, phase transformation temperatures and mechanical properties were investigated for Ti-Ni shape memory alloys. Ti50Ni50-XRuX alloys with Ru contents (X) from 0mol% (binary TiNi) to 50mol% (binary TiRu) were systematically prepared by Ar arc-melting followed by hot-forging at temperatures from 1173K to 1673K depending on chemical composition. Phase stability was assessed by DSC (differential scanning calorimetry), XRD (X-ray diffractometry) and TEM (transmission electron microscopy). Mechanical properties were investigated using hardness and tensile tests at room temperature. With increasing Ru content, it was found that the lattice parameter of B2 phase increases, the martensitic transformation temperature slightly decreases, and the melting temperature increases monotonously. Besides, R-phase appears for Ti-Ni alloys containing 3mol% and 20mol%Ru but no diffusionless phase transformation is seen in Ti-Ni alloy containing 5mol%Ru. Vickers hardness shows the maximum at an intermediate composition (HV1030 at 30mol%Ru); this suggests that large solid solution hardening is caused by Ru substitution for the Ni-sites in TiNi.

Structure and Microwave Absorption Properties of Ho-Fe-Si Alloys

2018 ◽  
Vol 914 ◽  
pp. 117-123 ◽  
Author(s):  
Jia Liang Luo ◽  
Shun Kang Pan ◽  
Li Chun Cheng ◽  
Pei Hao Lin ◽  
Yu He ◽  
...  
Keyword(s):  
Ball Milling ◽  
Matching Condition ◽  
Peak Frequency ◽  
High Energy ◽  
X Ray Diffraction ◽  
Absorption Properties ◽  
Arc Melting ◽  
Microwave Absorbing Materials ◽  
Milling Method ◽  
Si Content

The Ho2Fe17-xSix (x=0.0, 0.1, 0.2, 0.3) alloys were prepared by arc melting and high energy ball milling method. The influence of the Si substitution on phase structure, morphology and electromagnetic parameters were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and vector network analyzer (VNA), respectively. The results show that the Ho-Fe-Si particles are flaky after the ball milling. The minimum absorption peak frequency shifts towards a lower frequency region with the increasing of Si content. The minimum RL of Ho2Fe16.7Si0.3 reaches-42.96 dB at 9.76 GHz, and the frequency bandwidth of R<-10 dB reaches about 2.64 GHz with the best matching condition d=1.6 mm. The reflection loss with the thickness ranging of 1.2-3.0 mm could reach-10 dB, which indicates the particles be considered as the promising microwave absorbing materials with a good absorption properties.

Microstructure and Oxidation Resistance of Cr-Ta-Si alloys

2011 ◽  
Vol 1295 ◽  
Author(s):  
Ayan Bhowmik ◽  
Hon Tong Pang ◽  
Steffen Neumeier ◽  
Howard J. Stone ◽  
Ian Edmonds
Keyword(s):  
Phase Equilibria ◽  
Oxidation Resistance ◽  
Ternary Phase Diagram ◽  
Intermetallic Phase ◽  
Ternary Alloys ◽  
Gravimetric Analysis ◽  
Silica Layer ◽  
X Ray Diffraction ◽  
Arc Melting ◽  
Si Content

ABSTRACTThe phase equilibria and oxidation resistance of alloys lying near the Cr-rich end of the Cr- Ta-Si system have been investigated. Samples were prepared by arc-melting and homogenized at 1300°C for 500hrs. Identification of the phases present and their compositions were carried out using x-ray diffraction and electron probe micro-analysis and the ternary phase diagram on the Cr-rich end was plotted. A three-phase equilibria was found to exist between an A2 Cr-solid solution, a hexagonal Laves phase and the A15 Cr3Si intermetallic phase for alloys with higher contents of Si.Thermo-gravimetric analysis of the alloys at 1100°C demonstrated an improvement in the oxidation resistance of the ternary alloys with increasing Si-content. The microstructures of the oxidized samples revealed the formation of a thick chromia layer on top of a Cr,Ta-mixed oxide layer and an internal oxidation zone for all the alloys. A protective silica layer was not observed to form in any of the alloys tested.

THE VARIATION OF EXCHANGE CONSTANT AND MAGNETOCALORIC EFFECT IN LaFe13-xSix (x = 1.6, 1.9 AND 2.2) COMPOUNDS

2011 ◽  
Vol 25 (25) ◽  
pp. 3303-3313 ◽  
Author(s):  
T. IZGI ◽  
V. S. KOLAT ◽  
H. GENCER ◽  
S. ATALAY
Keyword(s):  
Magnetocaloric Effect ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Wave Dispersion ◽  
Lattice Parameter ◽  
Exchange Constant ◽  
Magnetic Entropy ◽  
Arc Melting ◽  
Exchange Constants ◽  
Si Content

In this work, we present the variation of exchange constant (J exc ) and magnetocaloric effect (MCE) in LaFe 13-x Si x (x = 1.6, 1.9 and 2.2) compounds. NaZn 13-type LaFe 13-x Si x intermetallic compounds were prepared by arc melting in an atmosphere of highly pure argon gas. X-ray results indicated a slight decrease of lattice parameter with increasing Si content. The maximum magnetic entropy change of the LaFe 13-x Si x (x = 1.6, 1.9 and 2.2) samples decreases with increasing Si contents. Also, the magnetic entropy change was calculated theoretically at various magnetic fields and compared with experimental data. The spin-wave dispersion coefficients (D) and exchange constants (J exc ) were calculated for the fist time for these samples. It was found that D and J exc increase with increasing Si content.

scholarly journals Evolution of the ε and γ phases in biodegradable Fe–Mn alloys produced using laser powder-bed fusion

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Črtomir Donik ◽  
Jakob Kraner ◽  
Aleksandra Kocijan ◽  
Irena Paulin ◽  
Matjaž Godec
Keyword(s):  
Laser Power ◽  
Scanning Speed ◽  
Immersion Test ◽  
Pure Metal ◽  
Corrosion Stability ◽  
Powder Bed ◽  
Ε Phase ◽  
Mn Content ◽  
Static Immersion ◽  
Comprehensive Study

AbstractThe key feature of Fe–Mn alloys is gradual degradability and non-magneticity, with laser power bed fusion (LPBF) parameters influencing the microstructure and chemical composition. Our study focuses on biodegradable Fe–Mn alloys produced by mechanically mixing pure metal feedstock powders as part of the LPBF process. The Mn content and, consequently, the γ-ε phase formation in LPBF samples are directly correlated with an adapted energy–density (E) equation by combining the five primary LPBF parameters. We varied laser power (P) in a range of 200–350 W and scanning speed at 400 and 800 mm/s, and a comprehensive study was performed on samples with similar E. The study also showed an almost linear correlation between the LPBF's laser power and the material's hardness and porosity. The corrosion resistance was significantly reduced (from 13 to 400 μm/year) for the LPBF samples compared to a conventionally produced sample due to the dual-phase microstructure, increased porosity and other defects. The static immersion test showed that the process parameters greatly influence the quantity of oxides and the distribution of their diameters in the LPBF samples and, therefore, their corrosion stability. The most challenging part of the study was reducing the amount of ε phase relative to γ phase to increase the non-magnetic properties of the LPBF samples.

scholarly journals Evaluation of a Zn–2Ag–1.8Au–0.2V Alloy for Absorbable Biocompatible Materials

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 56 ◽  
Author(s):  
Ping Li ◽  
Christine Schille ◽  
Ernst Schweizer ◽  
Evi Kimmerle-Müller ◽  
Frank Rupp ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Antibacterial Properties ◽  
Microstructural Characterization ◽  
Immersion Test ◽  
Grain Refining ◽  
Degradation Behavior ◽  
New Generation ◽  
Phosphate Buffered Saline ◽  
Zn Alloy

Zinc (Zn) and Zn-based alloys have been proposed as a new generation of absorbable metals mainly owing to the moderate degradation behavior of zinc between magnesium and iron. Nonetheless, mechanical strength of pure Zn is relatively poor, making it insufficient for the majority of clinical applications. In this study, a novel Zn–2Ag–1.8Au–0.2V (wt.%) alloy (Zn–Ag–Au–V) was fabricated and investigated for use as a potential absorbable biocompatible material. Microstructural characterization indicated an effective grain-refining effect on the Zn alloy after a thermomechanical treatment. Compared to pure Zn, the Zn–Ag–Au–V alloy showed significantly enhanced mechanical properties, with a yield strength of 168 MPa, an ultimate tensile strength of 233 MPa, and an elongation of 17%. Immersion test indicated that the degradation rate of the Zn–Ag–Au–V alloy in Dulbecco’s phosphate buffered saline was approximately 7.34 ± 0.64 μm/year, thus being slightly lower than that of pure Zn. Biocompatibility tests with L929 and Saos-2 cells showed a moderate cytotoxicity, alloy extracts at 16.7%, and 10% concentration did not affect metabolic activity and cell proliferation. Plaque formation in vitro was reduced, the Zn–Ag–Au–V surface inhibited adhesion and biofilm formation by the early oral colonizer Streptococcus gordonii, indicating antibacterial properties of the alloy.

Degradation of Mechanically Surface Treated AZ31B Magnesium Alloy in 3.5 wt.% NaCl Solution

2019 ◽  
Vol 948 ◽  
pp. 237-242 ◽  
Author(s):  
Budi Arifvianto ◽  
Suyitno ◽  
Muslim Mahardika
Keyword(s):  
Magnesium Alloy ◽  
Immersion Test ◽  
Mg Alloy ◽  
Surface Mechanical Attrition Treatment ◽  
Degradation Behavior ◽  
Nacl Solution ◽  
Az31b Magnesium Alloy ◽  
Mechanical And Tribological Properties ◽  
Weight Losses ◽  
Mechanical Attrition

Surface mechanical attrition treatment (SMAT) has so far been used as a technique for improving mechanical and tribological properties of magnesium and its alloys. However, the effects of the SMAT on corrosion and degradability of these materials are still rarely reported in open literature. In this research, the degradation behavior of AZ31B magnesium alloy after receiving the SMAT was characterized. The degradation behavior of the Mg alloy was determined from the weight losses after an immersion test for 24 h in 3.5 wt.% NaCl solution. During the test, the pH of the solution was also monitored. The results obviously showed higher corrosion rates of the Mg alloy that had been treated by using the SMAT. Interestingly, the degradation rate of the Mg alloy decreased once a longer duration of SMAT was applied. Meanwhile, the pH of NaCl solution increased up to 12 and 13.9 once the non-treated and the SMAT specimens were immersed into the solution, respectively. In addition, the energy dispersive X-ray spectroscopy (EDS) analysis confirmed the presence of corrosion products in all the Mg samples that were similar to those revealed in the literature.

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