The Interface Microstructures and Mechanical Properties of Laser Additive Repaired Inconel 625 Alloy

The microstructure and micro-mechanics around the repaired interface, and the tensile properties of laser additive repaired (LARed) Inconel 625 alloy were investigated. The results showed that the microstructure around the repaired interface was divided into three zones: the substrate zone (SZ), the heat-affected zone (HAZ), and the repaired zone (RZ). The microstructure of the SZ had a typical equiaxed crystal structure, displaying simultaneously precipitated block-shaped MC-type carbides (NbC, TiC), with bimodal sizes of approximately 10 μm and 0.5 μm and an irregularly shaped flocculent Laves phase. Recrystallization occurred in the HAZ, and led to significant grain growth; a portion of the second phase dissolved in the original grain boundaries. In the RZ, there was a columnar crystal structure, and the size increased with increasing deposition thickness. Moreover, the microstructure between the layer interface and layer interior was quite different, presenting an overlapping transition zone (OTZ), in which the dendritic structure coarsened and more Laves phase were precipitated, compared to in the layer interior. The hardness and tensile properties of the LARed samples were equivalent to those of the wrought substrate, which indicates that laser additive repairing (LAR) is a reliable repair solution for damaged and mis-machined components comprising Inconel 625 alloy.

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Microstructures and Wear Resistance of Al1.5CrFeNiTi0.5 and Al1.5CrFeNiTi0.5W0.5 High Entropy Alloy Coatings Manufactured by Laser Cladding

Materials Science Forum ◽

10.4028/www.scientific.net/msf.956.154 ◽

2019 ◽

Vol 956 ◽

pp. 154-159 ◽

Cited By ~ 2

Author(s):

Hui Liang ◽

Bing Yang Gao ◽

Ya Ning Li ◽

Qiu Xin Nie ◽

Zhi Qiang Cao

Keyword(s):

Wear Resistance ◽

Laser Cladding ◽

Dendritic Structure ◽

Laves Phase ◽

High Entropy Alloy ◽

Second Phase ◽

Laves Phases ◽

High Entropy ◽

Two Phases ◽

Bcc Phase

For the purpose of expanding the application scope of HEA coating manufactured on the surface modification of materials, in this work, the Al1.5CrFeNiTi0.5 and Al1.5CrFeNiTi0.5W0.5 HEA coatings were successfully manufactured using laser cladding method on SUS304. The microstructures and wear resistance of coatings are researched systematically. It is found that the W0 and W0.5 HEA coatings all exhibit the dendritic structure, which are constituted by BCC phases and Laves phases. With W element addition, the phase structures of W0.5 coating remain unchanged. W is dissolved in both two phases, but the solid solubility in Laves phase is higher compared to that in BCC phase. W0.5 coating with the highest microhardness of 848.34 HV, and the W0 coating with the microhardness of 811.45 HV, both of whose microhardness are four times more than that of SUS304 substrate. Among all samples, the W0.5 coating shows the optimal wear performance because of its larger content of hard second phase ( Laves phase).

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Assessment of the Compositional Influences on the Toughness of TiCr2-Base Laves Phase Alloys

MRS Proceedings ◽

10.1557/proc-460-695 ◽

1996 ◽

Vol 460 ◽

Cited By ~ 2

Author(s):

Katherine C. Chen ◽

Samuel M. Allen ◽

James D. Livingston

Keyword(s):

Crystal Structure ◽

Single Phase ◽

Laves Phase ◽

Second Phase ◽

Vickers Indentation ◽

Toughening Mechanisms ◽

Two Phase ◽

Laves Phases ◽

Effective Factors ◽

Alloying Effects

ABSTRACTSystematic studies of alloys based on TiCr2 have been performed in order to improve the toughness of Laves phase intermetallics. The extent to which alloy compositions and annealing treatments influence the toughness was quantified by Vickers indentation. The single-phase Laves behavior was first established by studying stoichiometric and nonstoichiometric TiCr2. Next, alloying effects were investigated with ternary Laves phases based on TiCr2. Different microstructures of two-phase alloys consisting of (Ti,Cr)-bcc+TiCr2 were also examined. Various toughening theories based on vacancies, site-substitutions, crystal structure (C14, C36, or C15) stabilization, and the presence of a second phase were evaluated. The most effective factors improving the toughness of TiCr2 were determined, and toughening mechanisms are suggested.

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GTAW Welded Inconel 625 Alloy Fuel Cladding for the Canadian SCWR: Microstructure and Mechanical Property Characterization

Journal of Nuclear Engineering and Radiation Science ◽

10.1115/1.4049278 ◽

2020 ◽

Author(s):

German Cota-Sanchez ◽

Lin Xiao

Keyword(s):

Mechanical Properties ◽

Grain Growth ◽

Dendritic Structure ◽

Base Material ◽

Mechanical Tests ◽

Nuclear Industry ◽

Reactor Fuel ◽

Inconel 625 ◽

Fuel Cladding ◽

Inconel 625 Alloy

Abstract Inconel 625 is considered one of the candidate materials for reactor fuel cladding in the Canadian supercritical water reactor (SCWR) design. Gas tungsten arc welding (GTAW) is being evaluated as a joining technique for SCWR fuel cladding since this method is widely used to join components in the power and nuclear industry. During the GTAW process, the welding thermal cycle produces different types of microstructures in both the heat-affected zone (HAZ) and fusion zone (FZ) that affect the material's mechanical properties. A series of welding experiments at various weld conditions were performed using an automatic GTAW orbital process on Inconel 625 alloy tubing. Simple analytical heat conduction and grain growth models were developed to predict weld temperature profiles and metallurgical transformations. Weld characterization included mechanical tests, optical microscopy, scanning electron microscopy - energy dispersive spectroscopy (SEM-EDS) elemental analysis, and microhardness measurements. Weld microstructural characterization revealed that a characteristic dendritic structure was formed in the FZ, while the HAZ exhibited larger equiaxed grains than those found in the base material. SEM-EDS analysis showed no distinct alloying element segregation in both the HAZ and FZ. Welds produced with heat inputs of about 3.00 kJ/cm3 presented similar mechanical properties as those observed in the base material. In these welds, grain growth was homogenously minimized in the FZ. It is concluded that the effective welding heat input control can optimize the weld microstructure and the weld mechanical properties in Inconel 625 tubing used as Canadian SCWR reactor fuel cladding.

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Investigation on Double Wire Metal Inert Gas Welding of A7N01-T4 Aluminum Alloy in High-Speed Welding

High Temperature Materials and Processes ◽

10.1515/htmp-2018-0073 ◽

2019 ◽

Vol 38 (2019) ◽

pp. 317-325 ◽

Cited By ~ 3

Author(s):

Zhicheng Wei ◽

Rongzheng Xu ◽

Hui Li ◽

Yanxi Hou ◽

Xuming Guo

Keyword(s):

Crystal Structure ◽

Aluminum Alloy ◽

High Speed ◽

Weld Zone ◽

Dendritic Structure ◽

Inert Gas ◽

Tensile Fracture ◽

Hardness Profile ◽

Columnar Crystal ◽

Metal Inert Gas Welding

AbstractFour-millimeter thick A7N01-T4 aluminum alloy plates were welded by double wire metal inert gas welding (DWMW) in high welding speeds, ranging from 1100 to 1250 mm/min. The results show that a sound joint could be obtained at a high speed of 1200 mm/min using DWMW. The weld zone (WZ) in the joint showed a dendritic structure of equiaxed grains, and in the fusion zone (FZ), the microstructure existed as a fine equiaxed crystal structure about 100 µm in thickness. In the WZ adjacent to the FZ, elongated columnar crystal structure distributed along to the interface, and coarse microstructure in the heat affected zone (HAZ) were found, showing a typical rolling texture. The main precipitates in the WZ were assumed to be Fe-enriched phases, and Mg- and Zn-enriched phases. Tensile fracture generally occurred in the WZ adjacent to the FZ with a decrease in ductility, and it was consistent with the results of the microstructure analysis and hardness profile. The mean ultimate tensile strength and elongation of specimens were 302 MPa and 4.5 %, respectively.

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The Microstructure of Weld Overlay Ni-Base Alloy Deposited on Carbon Steel by CMT Method

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.231.119 ◽

2015 ◽

Vol 231 ◽

pp. 119-124 ◽

Cited By ~ 8

Author(s):

Monika Solecka ◽

Paweł Petrzak ◽

Agnieszka Radziszewska

Keyword(s):

Carbon Steel ◽

Base Alloy ◽

Dendritic Structure ◽

Inconel 625 ◽

Cold Metal Transfer ◽

Inconel 625 Alloy ◽

Second Phases ◽

Transfer Method ◽

Cold Metal ◽

Weld Overlays

Ni-base alloys, like Inconel 625, exhibit a high temperature corrosion and oxidation resistance. For this reason, these alloys are typically used as a one of the most important coating material and can be applied in a different environments and elements of devices having various applications. In this work, Inconel 625 was deposited onto a carbon steel P235GH by Cold Metal Transfer method. Due to the segregation of Ni, Cr, Nb and Mo elements the Inconel 625 weld overlays cladded on boiler pipes P235GH obtained the dendritic structure, with the formation of a second phases at the end of solidification. The presence of γ (with high dislocation density), the Laves and (Nb,Ti)C phases was revealed by means of TEM examinations. The multipoint EDS analysis confirmed the presence of low Fe concentration in the Inconel 625 alloy coatings. The concentration profiles of Ni, Cr, Mo and Nb performed across the dendritic structure showed segregation of these elements.

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Analysis of As-Built Microstructures and Recrystallization Phenomena on Inconel 625 Alloy Obtained via Laser Powder Bed Fusion (L-PBF)

Metals ◽

10.3390/met11040619 ◽

2021 ◽

Vol 11 (4) ◽

pp. 619

Author(s):

Thibaut De Terris ◽

Olivier Castelnau ◽

Zehoua Hadjem-Hamouche ◽

Halim Haddadi ◽

Vincent Michel ◽

...

Keyword(s):

Tensile Properties ◽

Austenitic Stainless Steels ◽

High Energy ◽

Energy Conditions ◽

Inconel 625 ◽

Powder Bed Fusion ◽

Laser Powder Bed Fusion ◽

Powder Bed ◽

Dislocation Densities ◽

Inconel 625 Alloy

The microstructures induced by the laser-powder bed fusion (L-PBF) process have been widely investigated over the last decade, especially on austenitic stainless steels (AISI 316L) and nickel-based superalloys (Inconel 718, Inconel 625). However, the conditions required to initiate recrystallization of L-PBF samples at high temperatures require further investigation, especially regarding the physical origins of substructures (dislocation densities) induced by the L-PBF process. Indeed, the recrystallization widely depends on the specimen substructure, and in the case of the L-PBF process, the substructure is obtained during rapid solidification. In this paper, a comparison is presented between Inconel 625 specimens obtained with different laser-powder bed fusion (L-PBF) conditions. The effects of the energy density (VED) values on as-built and heat-under microstructures are also investigated. It is first shown that L-PBF specimens created with high-energy conditions recrystallize earlier due to a larger density of geometrically necessary dislocations. Moreover, it is shown that lower energy densities offers better tensile properties for as-built specimens. However, an appropriate heat treatment makes it possible to homogenize the tensile properties.

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Morphology of Σ3{/70.53°} grain boundaries in a C15 intermetallic compound

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100171158 ◽

1994 ◽

Vol 52 ◽

pp. 684-685

Author(s):

Fuming Chu ◽

D. P. Pope ◽

D. S. Zhou ◽

T. E. Mitchell

Keyword(s):

Grain Boundary ◽

Grain Boundaries ◽

Crystallographic Analysis ◽

Laves Phase ◽

Second Phase ◽

Bright Field Image ◽

Boundary Edge ◽

Arc Melting ◽

Fcc Lattice ◽

Diffraction Patterns

A C15 Laves phase, HfV2+Nb, shows promising mechanical properties and here we describe the structure of its grain boundaries. The C15 Laves phase has a fcc lattice with a=7.4Å. An alloy of composition Hf14V64Nb22 (including a C15 matrix and a second phase of V-rich bcc solution) was made by arc-melting. The alloy was homogenized at 1200°C for 120h. Preliminary study concentrated on Σ3{<110>/70.53°} grain boundaries in the C15 phase using Philips 400T and CM 30 microscopes.The most-commonly observed morphology of Σ3{<110>/70.53°} grain boundaries in the C15 phase is a faceted boundary. A bright field image (BFI) of the faceted boundary and the corresponding diffraction patterns with the grain boundary edge-on are shown in Fig. 1(a). From the diffraction patterns using a <110> zone axis for both grains, it is obvious that this is a Σ3{<110>/70.53°} grain boundary. Crystallographic analysis shows that the Σ3{<110>/70.53°} grain boundaries selectively facet with the following relationships between the two grains: {111}1//{111}2, {112}1//{112}2, {111}1//{115}2, and {001}1//{221}2.

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Tool wear analysis in the turning of Inconel 625 alloy

10.26678/abcm.cobef2019.cof2019-0589 ◽

2019 ◽

Author(s):

Diego de Medeiros Barbosa ◽

Leticia Helena Guimarães Alvarinho ◽

Aristides Magri ◽

Daniel Suyama

Keyword(s):

Tool Wear ◽

Inconel 625 ◽

Wear Analysis ◽

Inconel 625 Alloy

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Corrosion behaviors of 316 stainless steel and Inconel 625 alloy in chloride molten salts for solar energy storage

High Temperature Materials and Processes ◽

10.1515/htmp-2020-0077 ◽

2020 ◽

Vol 39 (1) ◽

pp. 340-350

Author(s):

Mingjing Wang ◽

Song Zeng ◽

Huihui Zhang ◽

Ming Zhu ◽

Chengxin Lei ◽

...

Keyword(s):

Stainless Steel ◽

Molten Salt ◽

Electrochemical Impedance ◽

Charge Transfer Resistance ◽

Inconel 625 ◽

Transfer Resistance ◽

316 Stainless Steel ◽

Corrosion Rates ◽

Inconel 625 Alloy ◽

Corrosion Behaviors

AbstractCorrosion behaviors of 316 stainless steel (316 ss) and Inconel 625 alloy in molten NaCl–KCl–ZnCl2 at 700°C and 900°C were investigated by immersion tests and electrochemical methods, including potentiodynamic polarization and electrochemical impedance spectroscopy. X-ray diffraction and scanning electron microscopy/energy dispersive spectroscopy were used to analyze the phases and microstructures of the corrosion products. Inconel 625 alloy and 316 ss exhibited high corrosion rates in molten chlorides, and the corrosion rates of these two alloys accelerated when the temperature increased from 700°C to 900°C. The results of the electrochemical tests showed that both alloys exhibited active corrosion in chloride molten salt, and the current density of 316 ss in chloride molten salt at 700°C was 2.756 mA/cm−2, which is about three times the value for Inconel 625 alloy; and the values of the charge transfer resistance (Rt) for Inconel 625 were larger than those for 316 ss. The corrosion of these two alloys is owing to the preferred oxidation of Cr in chloride molten salt, and the corrosion layer was mainly ZnCr2O4 which was loose and porous and showed poor adherence to metal.

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