Thermal stability of surface treated zirconium Public Deposited

http://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/xw42nb47n

Descriptions

Attribute NameValues
Creator
Abstract or Summary
  • Zirconium press plates have been developed for the production of melamine coated particle board, using shot-peening to achieve the desired plate (and therefore coated particle board) surface texture. Service temperatures of the press plates approach 200°C. This study examined the microstructural effects of extended exposure of shot-peened zirconium to temperatures of 200°C and 300°C. Softening of the surface may reduce wear resistance and possibly the surface morphology of the plate, affecting the usability of the plates. It was discovered that the shot-peened surface of the plates experienced a loss in hardness from approximately 230 VHN (DPH) to about 220 VHN after 560 hrs at 200°C. The same drop in hardness was experienced after only 5.5 hrs at 300°C. This decrease in hardness was determined from hardness profiles before and after heat treating the zirconium to various times from 0.5 hours to 4458 hrs and 2790 hrs at 200°C and 300°C respectively. The decrease in hardness is believed to be a result of static recovery, the annihilation of point and/or line defects and/or alignment of dislocations into relatively low misorientation substantially relatively close to the shot-peened surface (about 35 μm), and decreased more modestly over the next 100 μm until virtually no drop was experienced further than approximately 150 μm from the surface. The shot-peening hardens the surface region which extends about 150 μm from the surface. Thus, the level of recovery appears to depend on the stored energy associated with cold work, or ambient temperature deformation. This increases from about 2-3% cold work (equivalent percent cold reduction from rolling) in the bulk of the specimens to near 99% at the surface resulting from shot-peening. The dislocation structure of the shot-peened zirconium was examined in the as-peened as well as the annealed conditions using transmission electron microscopy.
Resource Type
Date Available
Date Copyright
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Non-Academic Affiliation
Subject
Rights Statement
Peer Reviewed
Language
Digitization Specifications
  • File scanned at 300 ppi (Monochrome, 8-bit Grayscale) using ScandAll PRO 1.8.1 on a Fi-6670 in PDF format. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR
Replaces
Additional Information
  • description.provenance : Made available in DSpace on 2012-10-04T16:24:15Z (GMT). No. of bitstreams: 1 HayesTroyA1997.pdf: 4928294 bytes, checksum: 9706b7385e4a41618ad34330b3f2c587 (MD5) Previous issue date: 1996-06-14
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2012-10-04T16:24:15Z (GMT) No. of bitstreams: 1 HayesTroyA1997.pdf: 4928294 bytes, checksum: 9706b7385e4a41618ad34330b3f2c587 (MD5)
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2012-10-04T16:19:43Z (GMT) No. of bitstreams: 1 HayesTroyA1997.pdf: 4928294 bytes, checksum: 9706b7385e4a41618ad34330b3f2c587 (MD5)
  • description.provenance : Submitted by John Valentino (valentjo@onid.orst.edu) on 2012-10-03T21:16:59Z No. of bitstreams: 1 HayesTroyA1997.pdf: 4928294 bytes, checksum: 9706b7385e4a41618ad34330b3f2c587 (MD5)

Relationships

Parents:

This work has no parents.

Last modified

Downloadable Content

Download PDF

Items