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Effects of Preoxidation on the Strength and Fatigue of Hot-Pressed Silicon Nitride

  • K. Jakus
  • J. E. RitterJr.
  • W. Weinraub
  • W. S. Drooks
Part of the Materials Science Research book series (MSR, volume 14)

Abstract

The strength of as-machined and pre-oxidized hot-pressed silicon nitride was measured in three-point bending at temperatures of 23, 800, 1000, and 1100°C as a function of stressing rate. Pre-oxidation at 980°C for 50 h significantly increased the strength for the test temperatures of 23 and 800°C; however, at 1000°and 1100°C the strengths of pre-oxidized and as-machined samples were statistically indistinguishable and significantly less than the room temperature strengths. The fatigue resistance of the pre-oxidized specimens was found to be similar to that of the as-machined specimens at all temperatures with both exhibiting a high fatigue resistance (N=100) at 23 and 800°C and a significant decrease in fatigue resistance (N=20) at 1000 and 1100°C. Additional results showed that flaw generation and the growth of existing flaws are competing processes at high temperatures and fracture strength is determined by the most dominant of these processes.

Keywords

Silicon Nitride Subcritical Crack Growth Flaw Population Room Temperature Strength Proof Test 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Plenum Press, New York 1981

Authors and Affiliations

  • K. Jakus
    • 1
  • J. E. RitterJr.
    • 1
  • W. Weinraub
    • 1
  • W. S. Drooks
    • 1
  1. 1.Mechanical Engineering DepartmentUniversity of MassachusettsAmherstUSA

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