scholarly journals Effect of Aging Treatment on Intergranular Corrosion Properties of Ultra-Low Iron 625 Alloy

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Zhi-yuan Zhu ◽  
Yi Sui ◽  
An-lun Dai ◽  
Yuan-fei Cai ◽  
Ling-Li Xu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Intergranular Corrosion ◽  
Volume Fraction ◽  
Mass Loss Rate ◽  
Iron Alloy ◽  
Aging Treatment ◽  
Avrami Equation ◽  
Corrosion Properties ◽  
Alloy 625 ◽  
Precipitated Phase

The microstructures evolution of precipitations for an ultra-low iron Alloy 625 subjected to long term aging treatment at 750°C was investigated using scanning electron microscope (SEM) and X-ray diffraction (XRD). The intergranular corrosion behaviors of Alloy 625 were evaluated by using ASTM G28A. The result shows that the precipitated phase γ′′-Ni3Nb was mainly precipitated at the grain boundaries and twin boundaries. The number and volume fraction of γ′′ increased with the prolonging of aging time. The transformation of γ′′ to δ-Ni3Nb occurred after aging periods of 200 h. The corrosion resistance of Alloy 625 was significantly reduced during aging treatment. The decrease in intergranular corrosion resistance of Alloy 625 was attributed to the dissolution of precipitated phase and chromium depleted zone. The mass loss rate of Alloy 625 after aging treatment is related to the volume of precipitated phase and can be simulated by Johnson-Mehl-Avrami equation.

scholarly journals Long Term Aging Treatment Impact on Ultralow Iron Alloy 625 Intergranular Corrosion Property

2017 ◽  
Author(s):  
Zhi-yuan Zhu ◽  
Yi Sui ◽  
An-lun Dai ◽  
Yuan-fei Cai ◽  
Ling-li Xu ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Intergranular Corrosion ◽  
Iron Alloy ◽  
Aging Treatment ◽  
Corrosion Property ◽  
Avrami Equation ◽  
Gamma Phase ◽  
Alloy 625 ◽  
Delta Phase

This paper investigates the evolution of microstructures and precipitations of an ultra-low iron alloy 625 subjected to long term aging treatment by scanning electron microscope (SEM) and X-ray diffraction(XRD). Use ASTM G28A acid Fe3(SO4)2 erosion to represent intergranular corrosion weightlessness and corrosive morphology. The result shows that alloy at 750C by aging treatment for 40h, precipitated γ'' phase in the grain boundary. In high density area of γ'' phase, occurs γ'' phase to δ phase degeneration transformation by aging treatment for 200h and the needle-like δ phase becomes more with time prolonged. And γ'' phase degenerated to δ phase completely until treated for 1000h. The sample which has aging treatment tends to have intergranular corrosion and mainly because alloy element spreading leads to dilution area and grain boundary precipitated phase, plus interlaced δ phase’s dissolving, which makes sample grain particle fall off and this results in apparent weightlessness. The weightlessness rate(WLR) is related with precipitated volume score. With aging sensitization time change, can be described by Johnson-Mehl-Avrami equation, i.e.: WLR=44.32[ 1−exp( − t 10.99 ) ]+44.62[ 1−exp( − t 327.8 ) ]+1.267 ( mm/a ) MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVCI8FfYJH8 YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbba9q8WqFfeaY=biLkVcLq=J Hqpepeea0=as0Fb9pgeaYRXxe9vr0=vr0=vqpWqaaeaabiGaciaaca qabeaadaqaaqaafaGcbaaeaaaaaaaaa8qacaWGxbGaamitaiaadkfa cqGH9aqpcaaI0aGaaGinaiaac6cacaaIZaGaaGOmamaadmaapaqaa8 qacaaIXaGaeyOeI0IaaeyzaiaabIhacaqGWbWaaeWaa8aabaWdbiab gkHiTmaalaaapaqaa8qacaWG0baapaqaa8qacaaIXaGaaGimaiaac6 cacaaI5aGaaGyoaaaaaiaawIcacaGLPaaaaiaawUfacaGLDbaacqGH RaWkcaaI0aGaaGinaiaac6cacaaI2aGaaGOmamaadmaapaqaa8qaca aIXaGaeyOeI0IaaeyzaiaabIhacaqGWbWaaeWaa8aabaWdbiabgkHi Tmaalaaapaqaa8qacaWG0baapaqaa8qacaaIZaGaaGOmaiaaiEdaca GGUaGaaGioaaaaaiaawIcacaGLPaaaaiaawUfacaGLDbaacqGHRaWk caaIXaGaaiOlaiaaikdacaaI2aGaaG4naiaacckadaqadaWdaeaape GaamyBaiaad2gacaGGVaGaamyyaaGaayjkaiaawMcaaaaa@71FA@

Effect of heat treatment on microstructure and corrosion resistance of extruded ZK80 Mg alloy

2019 ◽  
Vol 9 (9) ◽  
pp. 1092-1099
Author(s):  
Fenghong Cao ◽  
Chang Chen ◽  
Zhenyu Wang
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Aging Time ◽  
Room Temperature ◽  
Aging Treatment ◽  
Corrosion Process ◽  
Corrosion Mechanism ◽  
Nacl Solution ◽  
Corrosion Properties

The corrosion characteristics and corrosion mechanism of the extruded ZK80 alloy with different states soaking in 3.5% NaCl solution at room temperature were analyzed via OM, SEM, EDS, XRD and static weightlessness method and other experimental analysis methods. The results show that when the aging temperature is constant, and the corrosion rate decreases with the lengthen of aging time, while when the corrosion time is constant, the corrosion rate increases with the increase in aging time. Appropriate aging treatment not only refines the grain of the alloy, but also precipitates the Mg–Zn phase which can effectively prevent the corrosion process and improve the anti-corrosion properties of the alloy. The main corrosion characteristics of the alloy are filamentary corrosion and pitting corrosion.

Wear and corrosion behavior of Mg-based alloy reinforced with TiC and ZrC particles

2020 ◽  
Vol 62 (12) ◽  
pp. 1161-1172
Author(s):  
Hülya Kaftelen Odabasi ◽  
Akın Odabasi
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Volume Fraction ◽  
Matrix Alloy ◽  
Az91 Alloy ◽  
Corrosion Properties ◽  
Wear Performance ◽  
Wear And Corrosion ◽  
Corrosion Mechanisms ◽  
Carbide Particles

Abstract In this contribution, particle sizes of TiC (13 and 93 μm) and volume fractions of ZrC (5 and 10 vol.-%) with respect to reinforcement particles were varied to investigate the effects on the microstructure, hardness, density, wear and corrosion properties of AZ91 Mg matrix alloy. Experimental results revealed that the hardness, density and sliding wear performance of AZ91 alloy were markedly improved by the addition of carbide particles. Predominant wear and corrosion mechanisms were identified considering the size and volume fraction of the carbides. The composite sample comprising fine TiC particles (13 μm) exhibited the highest wear resistance at the same volume fraction as the coarse particles. Moreover, coarse ZrC particles with a low volume fraction (5 vol.-%) provided an enhanced wear resistance beyond that of the 10 vol.-% ZrC particles. Considering all the investigated composites, the corrosion resistance of the composites deteriorated with the increasing volume fraction and size of the carbide particles. Electrochemical measurements of the 0,5M NaCl solution revealed that increasing carbide particle size and volume fraction leads to lower corrosion resistance due to the formation of more cathodic areas which are preferred sites for the initiation of pitting corrosion.

Influences of Aging Precipitation on Corrosion Resistance of 18Cr-18Mn-2Mo-0.77N HNS

2009 ◽  
Vol 79-82 ◽  
pp. 1013-1016 ◽  
Author(s):  
Zu Rui Zhang ◽  
Hua Bing Li ◽  
Zhou Hua Jiang ◽  
Zhen Li ◽  
Bao Yu Xu
Keyword(s):  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Volume Fraction ◽  
Aging Treatment ◽  
High Nitrogen ◽  
Aging Precipitation ◽  
Pitting Corrosion Resistance ◽  
Nitrogen Steel ◽  
The Matrix ◽  
Nose Temperature

Influences of aging precipitation of Cr2N and Chi (χ) phases on the resistance to pitting corrosion and intergranular corrosion of 18Cr-18Mn-2Mo-0.77N high nitrogen steel (HNS) as a type of fundamental and structural materials were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD) pattern and electrochemical methods. Intergranular, cellular Cr2N and χ phases precipitate gradually along grain boundaries and inward grains. The volume fraction of precipitation presents a C-curve with a nose temperature of 850°C during 2h aging treatment. The solution-treated (ST) HNS exhibits the highest pitting corrosion potential because of high nitrogen content in steel, and especially no precipitation. The pitting corrosion resistance of aged HNS decreases because of the formation of aging precipitation which results in the depletion of Cr and Mo in the matrix. The pitting corrosion potentials firstly decrease then increase as the same tendency as the amount of precipitation expect 850°C and 900°C. Double loop electrochemical potentiokinetic reaction (DL-EPR) results show that the change tendency of IGC susceptibility is well consistent with the amount of precipitation of aged HNS for 2h at various temperatures. With prolonging the aging time at 850°C, aged HNS presents more obviously intergranular sensitization due to the formation of aging precipitation which results in the depletion of Cr and Mo.

scholarly journals Effects of Mn, Zn Additions and Cooling Rate on Mechanical and Corrosion Properties of Al-4.6Mg Casting Alloys

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1983
Author(s):  
Chih-Ting Wu ◽  
Sheng-Long Lee ◽  
Ye-Feng Chen ◽  
Hui-Yun Bor ◽  
Kung-Hui Liu
Keyword(s):  
Tensile Strength ◽  
Corrosion Resistance ◽  
Intergranular Corrosion ◽  
Continuous Distribution ◽  
Water Cooling ◽  
Dispersion Strengthening ◽  
Corrosion Properties ◽  
Casting Alloys ◽  
Mechanical And Corrosion Properties ◽  
Al Mg Alloys

The mechanical properties of the Al-Mg alloy can be enhanced by adding metallic elements, but a continuous distribution of precipitates at grain boundaries leads to intergranular corrosion during sensitization treatment. In the present work, Mn, Zn additions, water cooling and furnace cooling were executed to investigate their effects on the mechanical and corrosion properties of the Al-4.6Mg alloy. Our results show that adding Mn to Al-4.6Mg alloys may produce grain refinement and dispersion strengthening, increasing tensile strength and hardness. The presence of Mn did not affect the corrosion resistance of Al-Mg alloys. Adding Zn to the Al-4.6Mg alloy increased tensile strength and hardness, but decreased corrosion resistance. Combined, the addition of Mn and Zn to the Al-4.6Mg alloy exhibited the highest tensile strength and hardness, but seriously reduced corrosion resistance. Furnace cooling substituted for water quenching could avoid intergranular corrosion, but slightly decreased the tensile strength and hardness by 7.0% and 6.8%, respectively.

scholarly journals Effect of Combined Extrusion and Rolling Parameters on Mechanical and Corrosion Properties of New High Strength Al-Mg Alloy

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 445
Author(s):  
Kweon-Hoon Choi ◽  
Bong-Hwan Kim ◽  
Da-Bin Lee ◽  
Seung-Yoon Yang ◽  
Nam-Seok Kim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Current Density ◽  
Intergranular Corrosion ◽  
Artificial Aging ◽  
Corrosion Potential ◽  
Volume Fraction ◽  
High Strength ◽  
Mg Alloy ◽  
Corrosion Properties

High strength Al-Mg alloy is an attractive material that has the characteristic of increasing both strength and elongation by adding more solute Mg. However, there is a limitation in the oxidation issue during the casting process when it contains high amounts of solute Mg. New Al-Mg alloy was developed using Mg+Al2Ca master alloy by making a stable CaO/MgO mixed layer that no significant oxidation occurred. Here, the intergranular corrosion (IGC), electrochemical, and mechanical properties of new Al-Mg alloys fabricated through a combined process of extrusion and cold rolling were studied after the specimens went through artificial aging heat treatment at 200 °C. The results show that the grain size and the volume fraction of anodic β-precipitation (Mg2Al3) forming on the grain boundary influence the intergranular corrosion results. Corrosion potential and current density were achieved by potentiodynamic polarization electrochemical test. The results show that corrosion potential remains irrespective of the manufacturing process, while current density increases with artificial aging treatment. Both hardness and tensile mechanical properties decrease on cold rolled specimens after the heat treatment, while increase in extrusion and annealed specimens.

scholarly journals Avials, history of creation and overview of future outlook

2021 ◽  
Vol 98 (2) ◽  
pp. 23-37
Author(s):  
A.V. Sinchuk ◽  
Keyword(s):  
Corrosion Resistance ◽  
Transition Metals ◽  
Intergranular Corrosion ◽  
Negative Impact ◽  
Recrystallization Temperature ◽  
Corrosion Properties ◽  
Alloying System ◽  
Quench Sensitivity ◽  
Multi Stage ◽  
History Of

Scientific domestic and foreign literature touching the field of Al – Mg – Si wrought aluminum alloys are reviewed, the history of appearance of the most common brands is described. It is shown that the development of alloys was proceed gradually advancing their chemical composition along the quasi-binary Mg/Si = 1.73 сross -section in the direction of increasing concentration of just Mg and Si, and the strength of last modern brands was provided by additional alloying, primarily copper, the content of which can reach 1-1.4%. The influence of alloying elements on microstructure, mechanical and corrosion properties of alloys is described, features of their heat treatment, factors of maximum strengthening and susceptibility to intergranular corrosion are revealed. Attention is focused on the key role of the Mg/Si ratio, transition metals, Cu, Cr and Mn first of all, in the formation of balanced properties, since the positive effect of these elements on increasing the strength and the recrystallization temperature is often offset by the negative impact on intergranular corrosion and quench sensitivity. It is shown that in low-alloyed Al–Mg–Si alloys the strength premises Mg/Si≈1 and the premises for high-end corrosion resistance Mg/Si≈2 are occurred simultaneously. Alongside an increase of the absolute content of Mg and Si in alloys, alongside an increase of alloying degree with other strengthening elements, it is impossible to simultaneously fulfill both of these premises; therefore, one has to look for a reasonable compromise between strengthening, decreasing the technological plasticity and corrosion resistance of alloys. One of the effective ways to reach such a compromise is multi-stage regimes of artificial aging. The prospects of microalloying with Sc and Ca able to form with aluminum nanoscale intermetallic phases of hardening are outlined. Keywords: avials, semi - finished products, alloying system, transition metals, aging, mechanical properties, intergranular corrosion.

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