Accession Number:

ADA127583

Title:

Structural Reliability of Yttria-Doped, Hot-Pressed Silicon Nitride at Elevated Temperatures.

Descriptive Note:

Annual rept. 1 Oct 81-30 Sep 82,

Corporate Author:

NATIONAL BUREAU OF STANDARDS WASHINGTON DC

Personal Author(s):

Report Date:

1983-03-01

Pagination or Media Count:

32.0

Abstract:

The strength of yttria-doped, hot-pressed silicon nitride was investigated as a function of temperature and applied load. Data collected 1200 degrees C are presented in the form of a strength degradation diagram for an applied load of 350 MPa. At this temperature, the behavior of the yttria-doped material is found to be superior to that of magnesia-doped silicon nitride, in which creep results in the formation of microcracks that lead to strength degradation. By contrast, the ytrria-doped material does not suffer from microcrack formation, or strength degradation at 1200 degrees C. At higher temperatures strength degradation does occur, and as a consequence, an upper limit of 1200 degrees C is recommended for ytrria-doped, hot-pressed silicon nitride in structural application. Author

Subject Categories:

  • Ceramics, Refractories and Glass
  • Properties of Metals and Alloys
  • Test Facilities, Equipment and Methods
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE