Spinodal Decomposition and Order-Disorder Transformation in a Water-Quenched U-6wt%Nb Alloy

PDF Version Also Available for Download.

Description

A combinative approach of microhardness testing, tensile testing, and TEM microstructural analysis has been employed to study phase stability and aging mechanisms of a water-quenched U-6wt%Nb (WQU6Nb) alloy subjected to different aging schedules that include artificial aging of WQ-U6Nb at 200 C, natural aging of WQ-U6Nb at ambient temperatures for 15 to18 years, and accelerative aging of the naturally aged (NA) alloy at 200 C. During the early stages of artificial aging at 200 C, the microhardness values continuously increase as a result of the development of a fine-scale compositional modulation (wavelength: 3 nm) caused by spinodal decomposition. Coarsening of ... continued below

Physical Description

PDF-file: 30 pages; size: 3 Mbytes

Creation Information

Hsiung, L & Zhou, J September 12, 2006.

Context

This report 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 report can be viewed below.

Who

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

Authors

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 report. Follow the links below to find similar items on the Digital Library.

Description

A combinative approach of microhardness testing, tensile testing, and TEM microstructural analysis has been employed to study phase stability and aging mechanisms of a water-quenched U-6wt%Nb (WQU6Nb) alloy subjected to different aging schedules that include artificial aging of WQ-U6Nb at 200 C, natural aging of WQ-U6Nb at ambient temperatures for 15 to18 years, and accelerative aging of the naturally aged (NA) alloy at 200 C. During the early stages of artificial aging at 200 C, the microhardness values continuously increase as a result of the development of a fine-scale compositional modulation (wavelength: 3 nm) caused by spinodal decomposition. Coarsening of the modulated structure occurs after prolonged aging of WQ-U6Nb at 200 C for 16 hours, which leads to a decrease of microhardness. Phase instability has also been found to occur in the NA alloy, in which the formation of partially ordered phase domains resulting from an atomic-scale spinodal modulation (wavelength: 0.5 nm) renders the appearance of antiphase domain boundaries (APBs) in TEM images. Although 18-year natural aging does not cause a significant change in hardness, it affects dramatically the aging mechanism of WQ-U6Nb subjected to the accelerative aging at 200 C. The result of microhardness measurement shows that the hardness values continuously increase until after aging for 239 hours, and the total hardness increment is twice in magnitude than that in the case of the artificial aging of water-quenched alloy at 200 C. The anomalous increment of hardness for the accelerative aging of NA alloy can be attributed to the precipitation of an ordered U{sub 3}Nb phase. It is accordingly concluded that the long-term natural aging at ambient temperatures can detour the transformation pathway of WQ U-6Nb alloy; it leads to the order-disorder transformation and precipitation of ordered phase in the alloy.

Physical Description

PDF-file: 30 pages; size: 3 Mbytes

Language

Item Type

Identifier

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

  • Report No.: UCRL-TR-224432
  • Grant Number: W-7405-ENG-48
  • DOI: 10.2172/900131 | External Link
  • Office of Scientific & Technical Information Report Number: 900131
  • Archival Resource Key: ark:/67531/metadc881270

Collections

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

Office of Scientific & Technical Information Technical Reports

What responsibilities do I have when using this report?

When

Dates and time periods associated with this report.

Creation Date

  • September 12, 2006

Added to The UNT Digital Library

  • Sept. 22, 2016, 2:13 a.m.

Description Last Updated

  • Dec. 7, 2016, 9:35 p.m.

Usage Statistics

When was this report last used?

Yesterday: 0
Past 30 days: 0
Total Uses: 2

Interact With This Report

Here are some suggestions for what to do next.

Start Reading

PDF Version Also Available for Download.

Citations, Rights, Re-Use

Hsiung, L & Zhou, J. Spinodal Decomposition and Order-Disorder Transformation in a Water-Quenched U-6wt%Nb Alloy, report, September 12, 2006; Livermore, California. (digital.library.unt.edu/ark:/67531/metadc881270/: accessed August 17, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.