Assessment of the high temperature deformation behavior of molybdenum silicide alloys

Jéhanno, P.; Heilmaier, Martin; Saage, Holger; Böning, M.; Kestler, H.; Freudenberger, J.; Drawin, Stefan

doi:10.1016/j.msea.2006.08.125

Cited by 76 publications

(51 citation statements)

References 20 publications

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“…This provides the desired metal-matrix microstructure reinforced with silicide phases [11,16,19]. In order to optimize the MA process, impact energy is adjusted to achieve satisfying powder quality and, at the same time, process parameters are balanced for economic reasons.…”

Section: Discussionmentioning

confidence: 99%

“…The mechanical properties of molybdenum and molybdenum solid solutions are significantly dependent on the type and the concentration of interstitials, e.g., oxygen, and alloying additions, for example Zr, Si, Nb or various oxides [10][11][12][13][14][15][16]. In many research studies molybdenum is alloyed with 6-13 at.…”

Section: Introductionmentioning

confidence: 99%

“…% silicon and 5-12 at. % boron aimed in the formation of silicides with an outstanding creep phases [11,16,19]. A variation of the rotational speed of the planetary ball mill and the type of grinding materials enables the variation of the impact energy and, therefore, helps to optimize this process.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Similarities and Differences in Mechanical Alloying Processes of V-Si-B and Mo-Si-B Powders

Krüger

Schmelzer

Helmecke

2016

Metals

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V-Si-B and Mo-Si-B alloys are currently the focus of materials research due to their excellent high temperature capabilities. To optimize the mechanical alloying (MA) process for these materials, we compare microstructures, morphology and particles size as well as hardness evolution during the milling process for the model alloys V-9Si-13B and Mo-9Si-8B. A variation of the rotational speed of the planetary ball mill and the type of grinding materials is therefore investigated. These modifications result in different impact energies during ball-powder-wall collisions, which are quantitatively described in this comparative study. Processing with tungsten carbide vials and balls provides slightly improved impact energies compared to vials and balls made of steel. However, contamination of the mechanically alloyed powders with flaked particles of tungsten carbide is unavoidable. In the case of using steel grinding materials, Fe contaminations are also detectable, which are solved in the V and Mo solid solution phases, respectively. Typical mechanisms that occur during the MA process such as fracturing and comminution are analyzed using the comminution rate K P . In both alloys, the welding processes are more pronounced compared to the fracturing processes.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Similarities and Differences in Mechanical Alloying Processes of V-Si-B and Mo-Si-B Powders

Krüger

Schmelzer

Helmecke

2016

Metals

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“…It is known from literature that the Mo solid solution should be the main carrier for high-temperature plastic deformation in Mo-Si-B alloys. [21][22][23] It is well known that creep rates increase with increasing grain boundary area. Therefore, single crystals materials are optimized for high temperature service.…”

Section: à3mentioning

confidence: 99%

Influence of Ingot and Powder Metallurgy Production Route on the Tensile Creep Behavior of Mo–9Si–8B Alloys with Additions of Al and Ge

2017

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Refractory metals and their alloys show potential for high temperature applications, due to the elevated melting points often paired with very good creep resistance. Spark plasma sintering (SPS) as well as arc-melting is used here to prepare quaternary and quinternary Mo-9Si-8B-xAl-yGe (x is 0 or 2; y is 0 or 2, all numbers in at%) samples. All samples consist of a Mo solid solution (Mo ss ) and two intermetallic phases: Mo 3 Si (A15) and Mo 5 SiB 2 (T2). Aluminum and germanium reduce the melting point and slightly decrease the density of the material. The specimens are homogenized and coarsened by a subsequent heat-treatment in vacuum at 1850C for 24 h. The resulting microstructure is investigated using scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), and inductively coupled plasma optical emission spectrometry (ICP-OES) analysis. A vacuum creep testing device for small tensile creep specimens is presented. It is heated by graphite radiation heaters usable up to 1500 C in vacuum of 2 Á 10 -4 Pa with an oil diffusion pump. Tensile creep tests are performed at 1250 C and stresses from 50 MPa up to 250 MPa. Specimens produced by ingot metallurgy feature superior creep properties compared to powder metallurgy samples.

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“…To deposit an Al-containing coating Sakidja et al [20] used the Al-pack cementation process which was already established for Ni-base superalloys. After subsequent annealing in air, the coated samples were protected against further oxidation by an outer Al 2 O 3 layer at all tested temperatures ranging from 732 to 1372 °C. Additionally, the coating consists of two more inner layers, (i) a mixture of Mo 3 Al 8 and Mo 3 Si and of (ii) Mo 3 Si and Mo 5 SiB 2 .…”

Section: Introductionmentioning

confidence: 99%

Enhanced Oxidation Resistance of Mo–Si–B–Ti Alloys by Pack Cementation

et al. 2017

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Abstract.As new high temperature structural materials, Mo-Si-B alloys satisfy several requirements such as oxidation and creep resistance. Recently, novel Ti-rich Mo-Si-B alloys have shown an increased creep resistance compared to Ti-free alloys. However, due to the formation of a duplex SiO 2 -TiO 2 oxide layer, which allows for fast ingress of oxygen, the oxidation resistance is poor. To improve the oxidation resistance a borosilicate based coating was applied to a Mo-12.5Si-8.5B-27.5Ti (in at.%) alloy. After co-deposition of Si and B by pack cementation at 1000 °C in Ar, a conditioning anneal at 1400 °C is used to develop an outer borosilicate layer followed by an inner MoSi 2 and Mo 5 Si 3 layer. During both isothermal and cyclic oxidation after an initial mass loss during the first hours of exposure, a steady state is reached for times up to 1000 h at temperatures ranging from 800 to 1200 °C demonstrating a significantly enhanced oxidation resistance.

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Assessment of the high temperature deformation behavior of molybdenum silicide alloys

Cited by 76 publications

References 20 publications

Similarities and Differences in Mechanical Alloying Processes of V-Si-B and Mo-Si-B Powders

Similarities and Differences in Mechanical Alloying Processes of V-Si-B and Mo-Si-B Powders

Influence of Ingot and Powder Metallurgy Production Route on the Tensile Creep Behavior of Mo–9Si–8B Alloys with Additions of Al and Ge

Enhanced Oxidation Resistance of Mo–Si–B–Ti Alloys by Pack Cementation

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