THERMAL SHOCK EVALUATION OF REFRACTORY MATERIALS AS ROCKET NOZZLE INSERTS
Abstract
Uninfiltrated sintered tungsten of several densities together with copper or silver infiltrated material used as rocket nozzle inserts were examined using a small scale nozzle but with operational temperature, pressure, and time duration of exposure. The nozzle insert walls were notched in a manner to produce stress raisers and their effects on the fracture patterns established relative ratings for resistance to thermal shock. Room temperature fracture toughness factors were also determined from notched bars of these same materials. This toughness factor served as a quality rating score to order the materials in their ability to resist fracture. It was found that copper infiltrated sintered tungsten rated highest on both the model test and on the fracture toughness scale. Mechanical strain induced in the outer surface of the nozzle insert by temperature gradients across the wall at the beginning of the ignition sequence together with the temperature were measured with the aid of several types of electrical resistance gages. These gages verified that cracking of the nozzle insert wall occurred early in the burning process.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 30, 1963
- Accession Number
- AD0430879
Entities
People
- E. W. Kammer
- Eugene Olcott
- Hillary L. Smith
Organizations
- United States Naval Research Laboratory