Search NASA⌕ Search

SEARCH · Search NASA

Results for “Mo-Si-V”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

4 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Evolution of the Microstructure and Hardness of Fe-8Cr-2.1Mo-Si-V Die Steel at Different Cooling Rates after Hot Deformation

In this study, the effect of microstructure evolution, especially that involving the proeutectoid carbides, on hardness distribution of ledeburite steel containing 8% chromium content was investigated at different cooling rates after hot deformation. The continuous cooling transformation was carried out using a fully automatic transformation measuring apparatus under cooling rates in the range of 0.03-80 °C/s. The transformation temperatures, Ac1, Ac3 and Ms, were measured by dilatometry. A nanoindentation test was employed to evaluate the mechanical properties of the cooled specimens. The evolution of microstructure indicated that the proportion trend of the precipitated carbides was dependent on the cooling rates. In addition, a mixture of pearlite and proeutectoid carbides was observed under slow cooling rates in the range of 0.03-0.2 °C/s, for which only a martensite transformation took place in austenite, and the proeutectoid carbides precipitated negligibly at cooling rates greater than or equal to 10 °C/s. The results also showed that the nanohardness significantly decreased and then slowly increased to a stable value with increasing cooling rates, which was similar to the content trend of the carbides that precipitated during the cooling process.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Materials Data on V3Si2Mo3 by Materials Project

V3Mo3Si2 crystallizes in the trigonal R32 space group. The structure is three-dimensional. V is bonded in a 2-coordinate geometry to two equivalent Mo and four equivalent Si atoms. Both V–Mo bond lengths are 2.40 Å. There are two shorter (2.66 Å) and two longer (2.70 Å) V–Si bond lengths. Mo is bonded in a 2-coordinate geometry to two equivalent V and four equivalent Si atoms. There are two shorter (2.67 Å) and two longer (2.73 Å) Mo–Si bond lengths. Si is bonded to six equivalent V and six equivalent Mo atoms to form a mixture of edge and face-sharing SiV6Mo6 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on VSi4Mo by Materials Project

VMoSi4 is Titanium Disilicide-derived structured and crystallizes in the monoclinic P2 space group. The structure is three-dimensional. there are three inequivalent V2+ sites. In the first V2+ site, V2+ is bonded in a distorted q6 geometry to ten Si2- atoms. There are a spread of V–Si bond distances ranging from 2.50–2.71 Å. In the second V2+ site, V2+ is bonded in a distorted q6 geometry to ten Si2- atoms. There are a spread of V–Si bond distances ranging from 2.52–2.72 Å. In the third V2+ site, V2+ is bonded in a distorted q6 geometry to ten Si2- atoms. There are a spread of V–Si bond distances ranging from 2.50–2.71 Å. There are three inequivalent Mo6+ sites. In the first Mo6+ site, Mo6+ is bonded in a distorted q6 geometry to ten Si2- atoms. There are a spread of Mo–Si bond distances ranging from 2.56–2.69 Å. In the second Mo6+ site, Mo6+ is bonded in a distorted q6 geometry to ten Si2- atoms. There are a spread of Mo–Si bond distances ranging from 2.55–2.68 Å. In the third Mo6+ site, Mo6+ is bonded in a distorted q6 geometry to ten Si2- atoms. There are a spread of Mo–Si bond distances ranging from 2.55–2.69 Å. There are six inequivalent Si2- sites. In the first Si2- site, Si2- is bonded in a 10-coordinate geometry to one V2+, four Mo6+, and five Si2- atoms. There are a spread of Si–Si bond distances ranging from 2.51–2.71 Å. In the second Si2- site, Si2- is bonded in a 10-coordinate geometry to two V2+, three equivalent Mo6+, and five Si2- atoms. There are a spread of Si–Si bond distances ranging from 2.51–2.70 Å. In the third Si2- site, Si2- is bonded in a 10-coordinate geometry to one V2+, four Mo6+, and five Si2- atoms. There are a spread of Si–Si bond distances ranging from 2.50–2.71 Å. In the fourth Si2- site, Si2- is bonded in a 10-coordinate geometry to four V2+, one Mo6+, and five Si2- atoms. There are a spread of Si–Si bond distances ranging from 2.46–2.74 Å. In the fifth Si2- site, Si2- is bonded in a 10-coordinate geometry to three equivalent V2+, two Mo6+, and five Si2- atoms. There are a spread of Si–Si bond distances ranging from 2.57–2.73 Å. In the sixth Si2- site, Si2- is bonded in a 10-coordinate geometry to four V2+, one Mo6+, and five Si2- atoms. There are a spread of Si–Si bond distances ranging from 2.59–2.72 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on VSi3Mo4 by Materials Project

Mo4VSi3 crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. V4+ is bonded to four equivalent Si4- atoms to form VSi4 tetrahedra that share corners with sixteen equivalent MoSi6 pentagonal pyramids, edges with eight equivalent MoSi6 pentagonal pyramids, and edges with two equivalent VSi4 tetrahedra. All V–Si bond lengths are 2.53 Å. Mo2+ is bonded to six Si4- atoms to form distorted MoSi6 pentagonal pyramids that share corners with fifteen equivalent MoSi6 pentagonal pyramids, corners with four equivalent VSi4 tetrahedra, edges with three equivalent MoSi6 pentagonal pyramids, edges with two equivalent VSi4 tetrahedra, and faces with seven equivalent MoSi6 pentagonal pyramids. There are a spread of Mo–Si bond distances ranging from 2.57–2.77 Å. There are two inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 10-coordinate geometry to eight equivalent Mo2+ and two equivalent Si4- atoms. Both Si–Si bond lengths are 2.42 Å. In the second Si4- site, Si4- is bonded in a 10-coordinate geometry to two equivalent V4+ and eight equivalent Mo2+ atoms.

36 MATERIALS SCIENCE↗