Microstructure and strengthening mechanisms of molybdenum alloy wires doped with lanthanum oxide particles

Zhang, Guojun; Liu, Gang; Sun, Yuanjun; Jiang, F.; Wang, Lin; Wang, Ruihong; Sun, Jun

doi:10.1016/j.ijrmhm.2008.06.007

Cited by 46 publications

(11 citation statements)

References 10 publications

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“…Due to its high fusion point, excellent mechanical properties and low neutron absorption cross-section [1,2,3], nanostructured high-strength molybdenum alloy (NS-Mo) has been selected as one of the candidate materials of the next generation Accident Tolerant Fuel (ATF) to avoid accidents such as that occurring at the Fukushima Nuclear Power Station in 2011. NS-Mo alloy is strengthened by doping with nano-sized rare earth oxide and shows an elongation of about 40% and a strength of about 700 MPa during tensile tests at room-temperature [4].…”

Section: Introductionmentioning

confidence: 99%

Effect of Heat Input on Porosity Defects in a Fiber Laser Welded Socket-Joint Made of Powder Metallurgy Molybdenum Alloy

Xie

Shang

et al. 2019

Materials

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Porosity defects are still a challenging issue in the fusion welding of molybdenum and its alloys due to the pre-existing interior defects associated with the powder metallurgy process. Fiber laser welding of end plug and cladding tube made of nanostructured high-strength molybdenum (NS-Mo) alloy was performed in this work with an emphasis on the role of welding heat input. The distribution and morphology of porosity defects in the welded joints were examined by computed tomography (CT) and scanning electron microscopy (SEM). Preliminary results showed that laser welding of NS-Mo under low heat input significantly reduced the porosity defects in the fusion zone. The results of computed tomography (CT) showed that when the welding heat input decreased from 3600 J/cm (i.e., 1200 W, 0.2 m/min) to 250 J/cm (i.e., 2500 W, 6 m/min), the porosity ratio of the NS-Mo joints declined from 10.7% to 2.1%. Notable porosity defects under high heat input were related to the instability of the keyhole, expansion and the merging of bubbles in the molten pool, among which the instability of the keyhole played the dominant role. The porous defects at low heat input were generated as bubbles released from the powder metallurgy base metal (BM) did not have enough time to overflow and escape.

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Section: Introductionmentioning

confidence: 99%

Effect of Heat Input on Porosity Defects in a Fiber Laser Welded Socket-Joint Made of Powder Metallurgy Molybdenum Alloy

Xie

Shang

et al. 2019

Materials

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“…Molybdenum alloy has the advantages of a high fusion point, high heat conductivity and a low neutron absorption cross-section [1][2][3]. In order to delay the deterioration of that may lead to serious accidents and allow for more time to take emergency measures, the newly developed nanostructured molybdenum alloy (NS-Mo) has been selected as one of the candidate materials for the cladding tube in nuclear fuel.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and Mechanical Properties of a Fiber Welded Socket-Joint Made of Powder Metallurgy Molybdenum Alloy

Xie

Shang

et al. 2019

Metals

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Fiber welding of socket-joints made of nanostructured high-performance molybdenum alloy (NS Mo) was carried out to get a better understanding of the role of welding heat input. It was found that low heat input (i.e., high welding speed) resulted in significantly refined grains in the fusion zone (FZ) of fiber laser welded NS Mo joints. When welding heat input decreased from 3600 J/cm (i.e., 1.2 kW, 20 cm/min) to 250 J/cm (i.e., 2.5 kW, 600 cm/min), the tensile strength of welded joints increased from about 250 MPa to about 570 MPa. It was confirmed by energy spectrum analysis that the higher the welding heat input, the higher the oxygen contents at the grain boundary (GB) within the FZ. In addition, the most important reason for poor strength of welded joints of Mo alloys was reported as being that MoO2 was segregated on the grain boundary. Therefore, it was concluded that welding under low heat input (i.e., high welding speed) was able to reduce the segregation degree of MoO2 at the grain boundary by refining grains and increasing the total area of GBs, thus improving the strength of welded joints and reducing the proportion of the intergranular fracture zone in tensile fractures.

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“…Additions of such RE elements as Er, Sc, Ce and La were studied with regard of their beneficial effects on the mechanical properties of aluminum alloys. The most benefits were obtained at low RE elements concentrations [13][14][15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Effects of CeO2 on the microstructure and properties of 2A12 porous aluminum

Liu

et al. 2018

SN Appl. Sci.

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The micron porous aluminum has received considerable attention in various domains, and the research of rare earths for the synthesis of materials with improved mechanical performance. In the present work, 2A12 aluminum alloys with different porosities were successfully prepared by cold pressing-vacuum sintering-dissolution process (SDP) with the CeO 2 additive, and the CeO 2 content effect on the microstructure and mechanical properties of the porous aluminum alloys were investigated. The results show that the open-cell porous aluminum with uniform holes can be obtained by SDP. CeO 2 addition affects the microstructure of porous aluminum alloys and results in the formation of Al 11 Ce 3 phase in specimens, which can enhance mechanical properties of the alloys. With increasing content of CeO 2 , all the specimens have a trend of increasing first and then decreasing, and when the CeO 2 content equal to 0.2 wt%, the tensile and compression strengths of porous aluminum with different porosities achieved the maximum value. Keywords 2A12 porous aluminum • CeO 2 • Microstructure • Al 11 Ce 3 • Tensile and compression strengths

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Microstructure and strengthening mechanisms of molybdenum alloy wires doped with lanthanum oxide particles

Cited by 46 publications

References 10 publications

Effect of Heat Input on Porosity Defects in a Fiber Laser Welded Socket-Joint Made of Powder Metallurgy Molybdenum Alloy

Effect of Heat Input on Porosity Defects in a Fiber Laser Welded Socket-Joint Made of Powder Metallurgy Molybdenum Alloy

Microstructure and Mechanical Properties of a Fiber Welded Socket-Joint Made of Powder Metallurgy Molybdenum Alloy

Effects of CeO2 on the microstructure and properties of 2A12 porous aluminum

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