Microstructure and hardness studies of the electron beam welded zone of Hastelloy C-276

Ahmad, Mushtaq; Akhter, J.I.; Akhtar, Mubeena; Iqbal, Mazhar; Ahmed, Ejaz; Choudhry, M. Arshad

doi:10.1016/j.jallcom.2004.08.031

Cited by 106 publications

(26 citation statements)

References 11 publications

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“…However, precipitates are not found in the twin grain boundaries. From the literature [8][9][10][11] , we know that the C276 alloy consists of EULWWOH ȝ SKDVH along with a small amount of M 6 C carbides. TEM image of alloy precipitation at 700°C aging 720h is given in Fig.4, and the corresponding analysis results of EDS are shown in Table 2.…”

Section: Microstructure Of Aged Alloymentioning

confidence: 99%

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Effect of Long Time Thermal Exposure on Microstructure and Mechanical Properties of C276 Superalloy

Lu¹,

Liu²,

Li³

et al. 2013

Pricm

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Due to the perfect mechanical properties and acceptable corrosion resistance, nickel-based superalloy C276 has been selected as the primary structure material of the experimental loop in thorium molten salt reactor (TMSR) program. In this work, microstructures and mechanical properties of C276 after long time exposure at700 have been investigated. SEM and TEM results indicate that the major precipitations of the alloy are ȝ SKDVH DQG 0 6 C carbides, which dispersing at grain boundary are transformed gradually to continuous-chain distribution with aging time. The VKDSHV RI ȝ Shase are massive, layered and needle-like. The increase of tensile strength and decrease of elongation have been observed with aging time, which relate to ȝ phase at both grain boundary and grain interior of the aged alloy. The optimum of ductility is obtained at 700°C for 720h and the high temperature tensile fracture presents ductility feature.

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Section: Microstructure Of Aged Alloymentioning

confidence: 99%

“…The stacking fault morphology is shown in ȝ SKDVH DQG LWV FU\VWDO structure belongs to the hexagonal system, which is consistent with the description of the literature. [8][9][10][11] …”

Section: Microstructure Of Aged Alloymentioning

confidence: 99%

Effect of Long Time Thermal Exposure on Microstructure and Mechanical Properties of C276 Superalloy

Lu¹,

Liu²,

Li³

et al. 2013

Pricm

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show abstract

“…12,13) However, due to lower cooling rate associated with conventional GTAW process, problems such solidification cracking, microfissuring, increased micro-segregation and precipitation of intermetallic compounds may arise which lead to immense decrease in mechanical as well as corrosion resistance of such dissimilar weldments. [14][15][16][17][18][19][20] In addition, slower cooling rate associated with such conventional welding techniques also results in coarser columnar dendritic structure and acts as a favorable site for segregation of elements while solidification. 21,22) Therefore, it is essential to improve the welding process in order to obtain better microstructural and mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Effect of Pulsed Current Gas Tungsten Arc Process on the Dissimilar Weldments between Nickel-based Superalloy/Austenitic Stainless Steel

2017

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The present work aims at investigating the microstructural and mechanical properties of dissimilar welds between Superalloy C-276 and Grade 321 austenitic stainless steel sheets, fabricated by pulsed current gas tungsten arc welding. The microstructural examination was carried out using an optical microscope and scanning electron microscope (SEM) equipped with energy dispersive spectroscopy. The weld metal microstructures divulged finer equiaxed grains. SEM images revealed migrated grain boundaries adjacent to weld line on both Superalloy C-276 and Grade 321. In addition, the presence of Mo-rich phases was also observed in the weld metal and at the weld interface of Superalloy C-276, which needs further investigation. Mechanical tests were carried out with respect to microhardness, tensile and impact properties. Furthermore, the presence of finer dendritic structure and controlled distribution of elements obtained with PCGTAW contributed for higher corrosion resistance of WM compared to BMs. The results of the present study would help in obtaining high quality dissimilar joints. Moreover, Grade 321 being a low-priced material as compared to Superalloy C-276 would be an economical substitution and would facilitate in saving huge material costs.

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“…Ahmad et al [8] studied the microstructure and hardness of the electron beam welded zone of 3-mm-thick Hastelloy C-276. The molten zone (MZ) was found to be of a fine lamellar type, and the hardness was 35% higher compared to as-received alloy, while a hardness reduction of about 5%-8% was observed in the HAZ.…”

Section: Introductionmentioning

confidence: 99%

The Effects of Pulse Parameters on Weld Geometry and Microstructure of a Pulsed Laser Welding Ni-Base Alloy Thin Sheet with Filler Wire

Chai

et al. 2016

Metals

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Due to its excellent resistance to corrosive environments and its superior mechanical properties, the Ni-based Hastelloy C-276 alloy was chosen as the material of the stator and rotor cans of a nuclear main pump. In the present work, the Hastelloy C-276 thin sheet 0.5 mm in thickness was welded with filler wire by a pulsed laser. The results indicated that the weld pool geometry and microstructure were significantly affected by the duty ratio, which was determined by the pulse duration and repetition rate under a certain heat input. The fusion zone area was mainly affected by the duty ratio, and the relationship was given by a quadratic polynomial equation. The increase in the duty ratio coarsened the grain size, but did not obviously affect microhardness. The weld geometry and base metal dilution rate was manipulated by controlling pulsed parameters without causing significant change to the performance of the weld. However, it should be noted that, with a larger duty ratio, the partial molten zone is a potential weakness of the weld.

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Microstructure and hardness studies of the electron beam welded zone of Hastelloy C-276

Cited by 106 publications

References 11 publications

Effect of Long Time Thermal Exposure on Microstructure and Mechanical Properties of C276 Superalloy

Effect of Long Time Thermal Exposure on Microstructure and Mechanical Properties of C276 Superalloy

Effect of Pulsed Current Gas Tungsten Arc Process on the Dissimilar Weldments between Nickel-based Superalloy/Austenitic Stainless Steel

The Effects of Pulse Parameters on Weld Geometry and Microstructure of a Pulsed Laser Welding Ni-Base Alloy Thin Sheet with Filler Wire

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