scholarly journals Characterization and Corrosion Resistance Behavior of Shape Memory Stainless Steel Developed by Alternate Routes

Metals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 13
Author(s):  
David Dias ◽  
Sandra Nakamatsu ◽  
Carlos Alberto Della Rovere ◽  
Jorge Otubo ◽  
Neide Aparecida Mariano
Keyword(s):  
Corrosion Resistance ◽  
Shape Memory ◽  
Dendritic Structure ◽  
Microstructural Characterization ◽  
Rolling Process ◽  
Chloride Ions ◽  
Secondary Phases ◽  
Electrochemical Tests ◽  
The Matrix ◽  
Routing Methods

The microstructural characterization and corrosion resistance behavior of Fe-Mn-Si-Cr-Ni alloy with shape memory effect was studied under different mechanical processing conditions and heat treatments, which were produced using conventional casting and routing methods to reduce costs and make production viable. Microstructural characterization was performed with electron microscopy and x-ray diffraction techniques, electrochemical tests with polarization, and thermogravimetry techniques. The cast condition presented a dendritic structure and the presence of the secondary phases: ferrite-δ and Chi-X phase. The heat treatment eliminated phases, reincorporated elements in the matrix, and increased the austenitic grain. After the hot rolling process, the alloy exhibited a refined microstructure with recrystallized austenitic grains. The heat-treated condition presented better oxidation resistance than the other conditions, while the hot-rolled condition showed repassivation of the pits, raising them to higher levels. All conditions presented low corrosion resistance in environments containing chloride ions.

scholarly journals Microstructural characterization of Cu82.3Al8.3Mn9.4 shape memory alloy after rolling

10.30544/314 ◽  
2017 ◽  
Vol 23 (3) ◽  
pp. 281-289
Author(s):  
Mirko Gojić ◽  
Stjepan Kožuh ◽  
Ivana Ivanić ◽  
Magdalena Selanec ◽  
Tamara Holjevac Grgurić ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Shape Memory Alloy ◽  
Cold Rolling ◽  
Shape Memory ◽  
Microstructural Characterization ◽  
Rolling Process ◽  
Scanning Calorimetry ◽  
Two Phase ◽  
Hot And Cold Rolling

In this paper, the microstructure of Cu82.3Al8.3Mn9.4 (in wt. %) shape memory alloy after hot and cold rolling was investigated. The Cu82.3Al8.3Mn9.4 alloy was produced by a vertical continuous casting method in the form a cylinder rod of 8 mm in diameter. After the casting, hot and cold rolling was performed. By hot rolling a strip with a thickness of 1.75 mm was obtained, while by cold rolling a strip with a thickness of 1.02 mm was produced. After the rolling process, heat treatment was performed. Heat treatment was carried out by solution annealing at 900 °C held for 30 minutes and water quenched immediately after heating. The microstructure characterization of the investigated alloy was carried out by optical microscopy (OM), scanning electron microscopy (SEM) equipped with a device for energy dispersive spectroscopy (EDS). Phase transformation temperatures and fusion enthalpies were determined by differential scanning calorimetry (DSC) method. The homogenous martensite microstructure was confirmed by OM and SEM micrographs after casting. During rolling the two-phase microstructure occurred. Results of DSC analysis showed martensite start (Ms), martensite finish (Mf), austenite start (As) and austenite finish (Af) temperatures.

Effect of Microalloy Elements on Corrosion Resistance of High-Chromium-Containing Ferritic Stainless Steels in Chloride Solutions

CORROSION ◽  
2001 ◽  
Vol 57 (6) ◽  
pp. 547-556 ◽  
Author(s):  
H. Kim ◽  
Y-D. Lee
Keyword(s):  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Stainless Steels ◽  
Mechanical Damage ◽  
Chemical Compositions ◽  
Inclusion Type ◽  
Electrochemical Tests ◽  
Pitting Corrosion Resistance ◽  
The Matrix ◽  
The Difference

Abstract The effects of inclusions on corrosion resistance of high-Cr-containing ferritic steels were studied using electrochemical tests (anodic polarization and electrochemical noise [EN]) and a ferric chloride (FeCl3) test in chloride solution. For this purpose, the inclusion type and size in the matrix was controlled by the selective addition of alloying elements, their contents, and pickling treatment. Large inclusions such as titanium nitride (TiN), though chemically stable, caused surface cracks at the inclusion/matrix interface during mechanical treatments and decreased pitting corrosion resistance. Soluble inclusions located at the interface were preferentially attacked to form crevices even if the inclusions were as small as a submicron. Meanwhile, submicron inclusions such as Nb, C, or N did not affect pitting corrosion resistance. Unlike the chemical compositions and shape of inclusion, the surface area covered by inclusions did not affect pitting corrosion resistance. Hence, the main factor affecting corrosion resistance was the presence of a crevice, whether it was formed by dissolution or mechanical damage, and not the number of inclusions. EN testing revealed that the experimental alloys deoxidized by Si were more resistant to initial pitting corrosion resistance than those deoxidized by Al, though many steel manufacturers deoxidize stainless steels by Al. The discrepancy was attributed to the difference of the chemical stability and the feasability of crack formation depending on inclusion.

scholarly journals Corrosion Resistance and Microstructure of Recasting Cobalt Alloys Used in Dental Prosthetics

2017 ◽  
Vol 17 (2) ◽  
pp. 63-68
Author(s):  
J. Loch ◽  
A. Krzykała ◽  
A. Łukaszczyk ◽  
J. Augustyn-Pieniążek
Keyword(s):  
Corrosion Resistance ◽  
Dendritic Structure ◽  
Passive Layer ◽  
Ceramic Mold ◽  
General Corrosion ◽  
Electrochemical Tests ◽  
Alloy Casting ◽  
Casting Alloys ◽  
Cobalt Solution ◽  
Dental Prosthetics

AbstractThe work presents the results of the studies of Co-Cr-Mo casting alloys used in the production of frame casts of removable dentures, crowns and bridges in dental prosthetics. The studies were performed on four Co-Cr-Mo alloys of different contents of Mo, W and other additives. Electrochemical tests were performed, which aimed at examining the corrosion resistance of the alloys and observing the alloy structure after chronoamperometric tests with the potential in the area of the occurrence of the passive layer breakpoint. The alloy microstructure images after chronoamperometric tests show the presence of non-uniformly distributed general corrosion. Moreover, a project of cobalt alloy casting was elaborated using a ceramic mold casting. Additionally, analysis of the obtained microstructure was performed. The microstructure of the examined alloys was of the dendrite type. This microstructure was chemically inhomogeneous and consisted of an austenitic matrix formed by a solid cobalt solution and chromium in the core dendritic structure.

scholarly journals Effect of Remelting of the Ni-22Cr-9Mo Alloy on its Microstructural and Electrochemical Properties

2017 ◽  
Vol 62 (1) ◽  
pp. 411-418 ◽  
Author(s):  
J. Augustyn-Nadzieja ◽  
A. Łukaszczyk ◽  
J. Loch
Keyword(s):  
Corrosion Resistance ◽  
Materials Science ◽  
Cast Alloy ◽  
Artificial Saliva ◽  
Dendritic Structure ◽  
Passive Layer ◽  
Commercial Alloy ◽  
Solution Ph ◽  
X Ray ◽  
Electrochemical Tests

AbstractThe Ni-Cr-Mo alloys are used as the alternative for the cobalt alloys in the manufacture of metal prosthetic elements, i.e. crowns, bridges and frame prostheses. The article attempts at a materials science characterization of the nickel-based alloy of the commercial name Argeloy N.P Be-Free by Argen. Within the study, examinations were made on the commercial alloy as well as the alloy which was remelted and cast by the los mould (lost wax) method. Observations of the microstructure were performed with the use of optical and electron scanning microscopy. Also, X-ray structural tests were conducted as well as corrosion resistance tests in an artificial saliva solution (pH = 6,7). It was demonstrated that the examined Ni-22Cr-9Mo alloy characterized in a dendritic structure typical of the cast materials. The X-ray qualitative phase analysis revealed the phase γ'(Ni) in both examined materials, as well as the presence of Cr23C6type carbides and Nb2C, Ta2C (commercial alloy) and NbC, Ta4C0,04(cast alloy) phases. The effect of the alloy’s remelting and the morphology of the passive layer on the corrosion resistance of the Ni-Cr-Mo alloy was examined.The results of the electrochemical tests show that the process of re-casting only slightly affects the corrosion resistance and the microstructure of the considered alloy.The roles of recasting process and the passive film homogeneity on the corrosion resistance of Ni-Cr-Mo dental alloy were reviewed. The results the electrochemical study show that the dependence of corrosion resistance on the microstructure associated with the recasting process is marginal.

COLMONOY 805

Alloy Digest ◽  
1998 ◽  
Vol 47 (12) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Abrasion Resistance ◽  
Coarse Particles ◽  
Powder Metal ◽  
Chromium Boride ◽  
Nickel Chromium ◽  
The Matrix

Abstract Colmonoy 805 is a nickel-chromium-boron alloy with coarse particles of chromium boride added to give it excellent sliding-type abrasion resistance. The alloy contains chromium boride in the matrix as large added particles. It is supplied only as a crushed powder for application with Colmonoy’s Fuseweld process. This datasheet provides information on composition, physical properties, microstructure, and elasticity. It also includes information on corrosion resistance as well as joining and powder metal forms.Filing Code: Ni-233. Producer or source: Wall Colmonoy Corporation. Originally published September 1976, revised December 1998.

scholarly journals Development of Al–Mg–Si alloy performance by addition of grain refiner Al–5Ti–1B alloy

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110294
Author(s):  
Khaled Abd El-Aziz ◽  
Emad M Ahmed ◽  
Abdulaziz H Alghtani ◽  
Bassem F Felemban ◽  
Hafiz T Ali ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Corrosion Resistance ◽  
Testing Machine ◽  
Dendritic Structure ◽  
Grain Refiner ◽  
Corrosion Properties ◽  
Average Grain Size ◽  
Structural Applications ◽  
Alloy Addition

Aluminum alloys are the most essential part of all shaped castings manufactured, mainly in the automotive, food industry, and structural applications. There is little consensus as to the precise relationship between grain size after grain refinement and corrosion resistance; conflicting conclusions have been published showing that reduced grain size can decrease or increase corrosion resistance. The effect of Al–5Ti–1B grain refiner (GR alloy) with different percentages on the mechanical properties and corrosion behavior of Aluminum-magnesium-silicon alloy (Al–Mg–Si) was studied. The average grain size is determined according to the E112ASTM standard. The compressive test specimens were made as per ASTM: E8/E8M-16 standard to get their compressive properties. The bulk hardness using Vickers hardness testing machine at a load of 50 g. Electrochemical corrosion tests were carried out in 3.5 % NaCl solution using Autolab Potentiostat/Galvanostat (PGSTAT 30).The grain size of the Al–Mg–Si alloy was reduced from 82 to 46 µm by the addition of GR alloy. The morphology of α-Al dendrites changes from coarse dendritic structure to fine equiaxed grains due to the addition of GR alloy and segregation of Ti, which controls the growth of primary α-Al. In addition, the mechanical properties of the Al–Mg–Si alloy were improved by GR alloy addition. GR alloy addition to Al–Mg–Si alloy produced fine-grained structure and better hardness and compressive strength. The addition of GR alloy did not reveal any marked improvements in the corrosion properties of Al–Mg–Si alloy.

scholarly journals Erosion and Corrosion Resistance Performance of Laser Metal Deposited High-Entropy Alloy Coatings at Hellisheidi Geothermal Site

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3071
Author(s):  
Andri Isak Thorhallsson ◽  
Francesco Fanicchia ◽  
Emily Davison ◽  
Shiladitya Paul ◽  
Svava Davidsdottir ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Microstructural Characterization ◽  
Corrosion Damage ◽  
Process Equipment ◽  
High Entropy Alloy ◽  
Low Alloy Steels ◽  
Manufacturing Defects ◽  
High Entropy ◽  
Alloy Steels ◽  
Resistance Performance

Geothermal process equipment and accessories are usually manufactured from low-alloy steels which offer affordability but increase the susceptibility of the materials to corrosion. Applying erosion-corrosion-resistant coatings to these components could represent an economical solution to the problem. In this work, testing of two newly developed laser metal deposited high-entropy alloy (LMD-HEA) coatings—CoCrFeNiMo0.85 and Al0.5CoCrFeNi, applied to carbon and stainless steels—was carried out at the Hellisheidi geothermal power plant. Tests in three different geothermal environments were performed at the Hellisheidi site: wellhead test at 194 °C and 14 bar, erosion test at 198 °C and 15 bar, and aerated test at 90 °C and 1 bar. Post-test microstructural characterization was performed via Scanning Eletron Microscope (SEM), Back-Scattered Electrons analysis (BSE), Energy Dispersive X-ray Spectroscopy (EDS), optical microscopy, and optical profilometry while erosion assessment was carried out using an image and chemical analysis. Both the CoCrFeNiMo0.85 and Al0.5CoCrFeNi coatings showed manufacturing defects (cracks) and were prone to corrosion damage. Results show that damage in the CoCrFeNiMo0.85-coated carbon steel can be induced by manufacturing defects in the coating. This was further confirmed by the excellent corrosion resistance performance of the CoCrFeNiMo0.85 coating deposited onto stainless steel, where no manufacturing cracks were observed.

scholarly journals Comparison of Structure and Properties of Mo2FeB2-Based Cermets Prepared by Welding Metallurgy and Vacuum Sintering

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 46
Author(s):  
Hu Xu ◽  
Junsheng Sun ◽  
Jun Jin ◽  
Jijun Song ◽  
Chi Wang
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Volume Fraction ◽  
Phase Evolution ◽  
304 Stainless Steel ◽  
Vacuum Sintering ◽  
Cored Wire ◽  
Welding Metallurgy ◽  
Metallurgical Bonding ◽  
The Matrix

At present, most Mo2FeB2-based cermets are prepared by vacuum sintering. However, vacuum sintering is only suitable for ordinary cylinder and cuboid workpieces, and it is difficult to apply to large curved surface and large size workpieces. Therefore, in order to improve the flexibility of preparing Mo2FeB2 cermet, a flux cored wire with 70% filling rate, 304 stainless steel, 60 wt% Mo powder and 40 wt% FeB powder was prepared. Mo2FeB2 cermet was prepared by an arc cladding welding metallurgy method with flux cored wire. In this paper, the microstructure, phase evolution, hardness, wear resistance and corrosion resistance of Mo2FeB2 cermets prepared by the vacuum sintering (VM-Mo2FeB2) and arc cladding welding metallurgy method (WM-Mo2FeB2) were systematically studied. The results show that VM-Mo2FeB2 is composed of Mo2FeB2 and γ-CrFeNi.WM-Mo2FeB2 is composed of Mo2FeB2, NiCrFe, MoCrFe and Cr2B3. The volume fraction of hard phase in WM-Mo2FeB2 is lower than that of VM-Mo2FeB2, and its hardness and corrosion resistance are also slightly lower than that of VM-Mo2FeB2, but there are obvious pores in the microstructure of VM-Mo2FeB2, which affects its properties. The results show that WM-Mo2FeB2 has good diffusion and metallurgical bonding with the matrix and has no obvious pores. The microstructure is compact and the wear resistance is better than that of VM-Mo2FeB2.

scholarly journals Influence of Shielding Gas on Microstructure and Properties of GMAW DSS2205 Welded Joints

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2671
Author(s):  
Xin-Yu Zhang ◽  
Xiao-Qin Zha ◽  
Ling-Qing Gao ◽  
Peng-Hui Hei ◽  
Yong-Feng Ren
Keyword(s):  
Corrosion Resistance ◽  
Welded Joints ◽  
Welded Joint ◽  
Crystal Defects ◽  
Shielding Gas ◽  
Electrochemical Tests ◽  
Corrosion Resistance Property ◽  
Mechanical Properties And Corrosion ◽  
Ar Gas ◽  
Welded Seam

In the present study, the microstructures and properties of DSS 2205 solid wire MIG welded samples prepared in different shielding gases (pure Ar gas, 98%Ar + 2%O2 and 98%Ar + 2%N2) were investigated for improving the weldability of DSS 2205 welded joint. The work was conducted by mechanical property tests (hardness and tensile test) and corrosion resistance property tests (immersion and electrochemical tests). The results show that adding 2%O2 into pure Ar gas as the shielding gas decreases crystal defects (faults) and improves the mechanical properties and corrosion resistance of the welded joints. Phase equilibrium and microstructural homogeneity in welded seam (WS) and heat-affected zone (HAZ) can be adjusted and the strength and corrosion resistance of welded joints increased obviously by adding 2%N2 to pure Ar gas as the shielding gas. Compared with DSS 2205 solid wire MIG welding in 98%Ar + 2%O2 mixed atmosphere, the strength and corrosion resistance of welded joints are improved more obviously in 98%Ar + 2%N2 mixed atmosphere.

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