Decrease of yield strength in molybdenum by adding small amounts of Group VIII elements

Hiraoka, Yutaka; Ogusu, Takayuki; Yoshizawa, Naoki

doi:10.1016/j.jallcom.2004.03.112

Cited by 24 publications

(7 citation statements)

References 17 publications

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“…Hardening was observed in W-Zr alloys [54] and softening in W-Re/Ir alloys [8]. Very interesting experimental results for Mo alloys with group VIIIA 3d transition metals were presented by Hiraoka et al [13]. The authors report a decrease of yield strength with addition of any element from group VIIIA, Fe, Co, Ni or 4d Pd.…”

Section: B Elastic Constantsmentioning

confidence: 99%

The influence of transition metal solutes on the dislocation core structure and values of the Peierls stress and barrier in tungsten

Samolyuk

Osetsky

Stoller

2012

J. Phys.: Condens. Matter

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Several transition metals were examined to evaluate their potential for improving the ductility of tungsten. The dislocation core structure and Peierls stress and barrier of 1/2<111> screw dislocations in binary tungsten-transition metal alloys (W(1-x)TM(x)) were investigated using density functional theory calculations. The periodic quadrupole approach was applied to model the structure of the 1/2<111> dislocation. Alloying with transition metals was modeled using the virtual crystal approximation and the applicability of this approach was assessed by calculating the equilibrium lattice parameter and elastic constants of the tungsten alloys. Reasonable agreement was obtained with experimental data and with results obtained from the conventional supercell approach. Increasing the concentration of a transition metal from the VIIIA group, i.e. the elements in columns headed by Fe, Co and Ni, leads to reduction of the C' elastic constant and increase of the elastic anisotropy A = C(44)/C'. Alloying W with a group VIIIA transition metal changes the structure of the dislocation core from symmetric to asymmetric, similarly to results obtained for W(1-x)Re(x) alloys in the earlier work of Romaner et al (2010 Phys. Rev. Lett. 104 195503). In addition to a change in the core symmetry, the values of the Peierls stress and barrier are reduced. The latter effect could lead to increased ductility in a tungsten-based alloy. Our results demonstrate that alloying with any of the transition metals from the VIIIA group should have a similar effect to alloying with Re.

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Section: B Elastic Constantsmentioning

confidence: 99%

The influence of transition metal solutes on the dislocation core structure and values of the Peierls stress and barrier in tungsten

Samolyuk

Osetsky

Stoller

2012

J. Phys.: Condens. Matter

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“…Because of the difficulty in achieving full-fic of Mo, much research focused on the enhancement of the sinterability. In this regard, one of the suggested processes for enhancing sinterability is the activated sintering process in which a metal such as Ni, Pt, Pd or Co is added to Mo [7][8][9][10][11][12][13]. However, these elements can degrade the electrical and thermal properties of the Mo.…”

Section: Introductionmentioning

confidence: 99%

Full Densification of Molybdenum Powders Using Spark Plasma Sintering

Mouawad

Soueidan

Fabrègue

et al. 2012

Metall Mater Trans A

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Pure molybdenum powder was sintered using Spark Plasma Sintering under various temperatures, and holding times, under a pressure of 77 MPa and a heating rate at 700°C/min. After sintering, a carbide layer was observed at the surface. The carbide layer thickness, the relative density of the sample as well as the microhardness and the grain size of Mo were measured. The carbide thickness depends on time and temperature and it was found that the carbide layer grows in a parabolic manner, with the activation energy of carbon diffusion in Mo being equal to 34 Kcal/mol. The densification of Mo is controlled mainly by the sintering temperature and the holding time. The molybdenum powder was successfully consolidated by SPS in short times. A relative density of 100% is achieved at a sintering temperature of 1850°C and a holding time of 30 minutes. It was shown that the hardness decreases slightly with temperature and time. It should be related to the increase in grain size with the sintering temperature and time.

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“…Because of the difficulty in achieving full-densification of Mo, much research has been focused on the enhancement of the sinterability. In this regard, one of the suggested processes for enhancing sinterability is the activated sintering process in which a metal such as Ni, Pt, Pd or Co is added to Mo [6][7][8][9][10][11][12]. However, these elements can cause deterioration of the electrical and thermal properties of the Mo.…”

Section: Introductionmentioning

confidence: 99%

Densification behavior of Mo nanopowders prepared by mechanochemical processing

Kim

et al. 2009

Journal of Alloys and Compounds

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Decrease of yield strength in molybdenum by adding small amounts of Group VIII elements

Cited by 24 publications

References 17 publications

The influence of transition metal solutes on the dislocation core structure and values of the Peierls stress and barrier in tungsten

The influence of transition metal solutes on the dislocation core structure and values of the Peierls stress and barrier in tungsten

Full Densification of Molybdenum Powders Using Spark Plasma Sintering

Densification behavior of Mo nanopowders prepared by mechanochemical processing

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