M5Si3(M=Ti, Nb, Mo) Based Transition-Metal Silicides for High Temperature Applications

PDF Version Also Available for Download.

Description

Transition metal silicides are being considered for future engine turbine components at temperatures up to 1600 C. Although significant improvement in high temperature strength, room temperature fracture toughness has been realized in the past decade, further improvement in oxidation resistance is needed. Oxidation mechanism of Ti{sub 5}Si{sub 3}-based alloys was investigated. Oxidation behavior of Ti{sub 5}Si{sub 3}-based alloy strongly depends on the atmosphere. Presence of Nitrogen alters the oxidation behavior of Ti{sub 5}Si{sub 3} by nucleation and growth of nitride subscale. Ti{sub 5}Si{sub 3.2} and Ti{sub 5}Si{sub 3}C{sub 0.5} alloys exhibited an excellent oxidation resistance in nitrogen bearing atmosphere due ... continued below

Physical Description

4602kb

Creation Information

Tang, Zhihong December 1, 2007.

Context

This thesis or dissertation is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided by UNT Libraries Government Documents Department to Digital Library, a digital repository hosted by the UNT Libraries. More information about this document can be viewed below.

Who

People and organizations associated with either the creation of this thesis or dissertation or its content.

Author

Publisher

Provided By

UNT Libraries Government Documents Department

Serving as both a federal and a state depository library, the UNT Libraries Government Documents Department maintains millions of items in a variety of formats. The department is a member of the FDLP Content Partnerships Program and an Affiliated Archive of the National Archives.

Contact Us

What

Descriptive information to help identify this thesis or dissertation. Follow the links below to find similar items on the Digital Library.

Description

Transition metal silicides are being considered for future engine turbine components at temperatures up to 1600 C. Although significant improvement in high temperature strength, room temperature fracture toughness has been realized in the past decade, further improvement in oxidation resistance is needed. Oxidation mechanism of Ti{sub 5}Si{sub 3}-based alloys was investigated. Oxidation behavior of Ti{sub 5}Si{sub 3}-based alloy strongly depends on the atmosphere. Presence of Nitrogen alters the oxidation behavior of Ti{sub 5}Si{sub 3} by nucleation and growth of nitride subscale. Ti{sub 5}Si{sub 3.2} and Ti{sub 5}Si{sub 3}C{sub 0.5} alloys exhibited an excellent oxidation resistance in nitrogen bearing atmosphere due to limited dissolution of nitrogen and increased Si/Ti activity ratio. MoSi{sub 2} coating developed by pack cementation to protect Mo-based Mo-Si-B composites was found to be effective up to 1500 C. Shifting coating composition to T1+T2+Mo{sub 3}Si region showed the possibility to extend the coating lifetime above 1500 C by more than ten times via formation of slow growing Mo{sub 3}Si or T2 interlayer without sacrificing the oxidation resistance of the coating. The phase equilibria in the Nb-rich portion of Nb-B system has been evaluated experimentally using metallographic analysis and differential thermal analyzer (DTA). It was shown that Nb{sub ss} (solid solution) and NbB are the only two primary phases in the 0-40 at.% B composition range, and the eutectic reaction L {leftrightarrow} Nb{sub SS} + NbB was determined to occur at 2104 {+-} 5 C by DTA.

Physical Description

4602kb

Language

Identifier

Unique identifying numbers for this document in the Digital Library or other systems.

  • Report No.: IS-T 2491
  • Grant Number: DE-AC02-07CH11358
  • Office of Scientific & Technical Information Report Number: 933031
  • Archival Resource Key: ark:/67531/metadc900760

Collections

This document is part of the following collection of related materials.

Office of Scientific & Technical Information Technical Reports

What responsibilities do I have when using this thesis or dissertation?

When

Dates and time periods associated with this thesis or dissertation.

Creation Date

  • December 1, 2007

Added to The UNT Digital Library

  • Sept. 27, 2016, 1:39 a.m.

Description Last Updated

  • Nov. 29, 2016, 7:16 p.m.

Usage Statistics

When was this document last used?

Congratulations! It looks like you are the first person to view this item online.

Interact With This Thesis Or Dissertation

Here are some suggestions for what to do next.

Start Reading

PDF Version Also Available for Download.

Citations, Rights, Re-Use

Tang, Zhihong. M5Si3(M=Ti, Nb, Mo) Based Transition-Metal Silicides for High Temperature Applications, thesis or dissertation, December 1, 2007; Ames, Iowa. (digital.library.unt.edu/ark:/67531/metadc900760/: accessed September 20, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.