The influence of silicon on the strength and fracture toughness of molybdenum

Sturm, Daniel; Heilmaier, Martin; Schneibel, J.H.; Jéhanno, P.; Skrotzki, Birgit; Saage, Holger

doi:10.1016/j.msea.2006.07.153

Cited by 126 publications

(50 citation statements)

References 21 publications

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“…3 shows the Mo lattice constant after 100 h of milling in dependence on Si addition. Here, the concentration of Si in solid solution was estimated by using the slope in Vegard's rule which was proven to be applicable to binary Mo-Si [39] (open squares in Fig. 3).…”

Section: Mechanical Alloying Of Binary Mo-si and Mo-b Powder Mixturesmentioning

confidence: 99%

Mechanically alloyed Mo–Si–B alloys with a continuous α-Mo matrix and improved mechanical properties

et al. 2008

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Section: Mechanical Alloying Of Binary Mo-si and Mo-b Powder Mixturesmentioning

confidence: 99%

Mechanically alloyed Mo–Si–B alloys with a continuous α-Mo matrix and improved mechanical properties

et al. 2008

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“…The strength, , of nanocrystalline Mo with grain size of from 97 to 180 nm is about 400 MPa. 22) Therefore, H Mo is estimated to be HV 1200 in this study, since H ¼ 3. The values of the terms for 6-h sintered compact are obtained from eq.…”

Section: Resultsmentioning

confidence: 80%

Microstructures and Mechanical Properties of (Ti<SUB>0.8</SUB>Mo<SUB>0.2</SUB>)C-30 mass% Ni without Core-Rim Structure

et al. 2010

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Mechanically alloyed powders having the composition (Ti 0:8 Mo 0:2 )C-30 mass% Ni were sintered at 1723 K for 2, 3, and 6 h. After sintering, a TiC phase without a core-rim structure and a Ni phase appeared. In addition, the X-ray diffraction spectrum of 6 h sintered compact showed a Mo peak. With an increase in the sintering time, the hard phase grain size, mean free path of the binder phase, and the binder phase volume fraction increased. The transverse rupture strength and Vickers hardness of the sintered compacts were measured. The maximum average transverse rupture strength was 1.51 GPa for 3-h sintered compact. The relationship between the hardness and the microstructure could be explained by the composite law including the structural factors. 2-h sintered compact had the highest hardness because of the relatively short mean free path of binder phase. 6-h sintered compact had the largest grain size, lowest volume fraction of the hard phase, and the longest mean free path of binder phase. However, this compact was harder than 3-h sintered compact because of the significantly high hard phase contiguity.

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“…Additionally, a Voronoi structure of similar composition to that of the real microstructure of Mo2.7Nb8.9Si7.7B alloy was simulated to proof whether Voronoi structures can represent a real homogeneous microstructure of a composite alloy. The input material properties for the analysis in the temperature range between RT and 1200°C for the Mo-0.5 wt.%Si solid solution matrix (a-Mo) were taken from work done by Sturm et al, [14] who evaluated the elastic properties at different temperatures using resonance method. For the T2 phase, Ihara et al determined the temperature dependent polycrystalline isotropic elastic moduli in the Hill average from the elastic stiffness constants by the resonance method.…”

Section: Resultsmentioning

confidence: 99%

FEM‐Simulation of Real and Artificial Microstructures of Mo‐Si‐B Alloys for Elastic Properties and Comparison with Analytical Methods

Biragoni

Heilmaier

2007

Adv Eng Mater

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In view of their outstanding intrinsic properties, notably the high melting point (approaching 2000°C) and, thus, the very good mechanical properties and creep strength at elevated temperatures, refractory metal (RM) silicide alloys are considered first choice replacements for Ni-base superalloys with the aim of increasing the (thermodynamic) efficiency of gas turbine engines. [1] Hence, the main objective of work on RM silicide alloys is to manufacture a composite material that takes advantage of (i) the beneficial oxidation resistance of the silicides and (ii) the outstanding mechanical properties of molybdenum. Nowotny et al, [2] first pointed out that alloys in the ternary system Mo-Si-B might be able to fulfil the above requirements. Later on, Berczik [3,4] followed up on this work and patented alloy compositions in the Mo-rich corner which were proved to possess balanced properties regarding high temperature creep strength, room temperature toughness and oxidation resistance. However, in his approach two manufacturing steps have appeared to be at least problematic to obtain sound material in sufficient quantities at reasonable costs: (1) Berczik employed a rapid solidification (RS) step via Helium gas atomization to obtain a matrix of Mo solid solution for adequate fracture toughness and ductility at temperatures below 600°C with embedded intermetallic compounds Mo 3 Si and Mo 5 SiB 2 (the T2 phase) for oxidation resistance due to the formation of a dense borosilicate glass layer on the metal surface, and (2) he also reported that for sound wrought processing temperatures above 1700°C were needed which makes industrial up-scaling hardly feasible.In order to overcome the above limitation (2) we suggested a powder-metallurgical manufacturing route with mechanical alloying (MA) as the technique replacing the (costly) RS gas atomization step to economically obtain large quantities of three phase Mo-Si-B material with a nearly continuous Mo solid solution matrix. [5] This material beneficially proved superplastic tensile deformation at temperatures as low as 1300°C, exhibiting an ultrafine microstructure with extraordinary thermal stability.Besides the above mentioned requirements applications as high temperature structural materials, for example as guide vanes in a turbine environment, also require the knowledge about the temperature dependent elastic properties and their dependence on microstructure. It is, therefore, the object of the present paper to combine an experimental and numerical approach for predicting the elastic properties of Mo-Si-B composite materials with varying microstructures. Experimental and Numerical Approach Microstructural characterizationThe microstructures of the samples were characterized by scanning electron microscopy (SEM) combined with energy dispersive X-ray microanalysis (JEOL 6400 SEM and FEI XL30 FEG equipped with EDX and EBSD). Three different alloy compositions and manufacturing routes were considered for subsequent modelling: while two cast alloys, Mo12Si8.5B and Mo12Si10...

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The influence of silicon on the strength and fracture toughness of molybdenum

Cited by 126 publications

References 21 publications

Mechanically alloyed Mo–Si–B alloys with a continuous α-Mo matrix and improved mechanical properties

Mechanically alloyed Mo–Si–B alloys with a continuous α-Mo matrix and improved mechanical properties

Microstructures and Mechanical Properties of (Ti<SUB>0.8</SUB>Mo<SUB>0.2</SUB>)C-30 mass% Ni without Core-Rim Structure

FEM‐Simulation of Real and Artificial Microstructures of Mo‐Si‐B Alloys for Elastic Properties and Comparison with Analytical Methods

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