Accession Number:

ADA616260

Title:

Mechanical Testing of Ultra-High Temperature Ceramics at 1500 C in Air - Development of an Experimental Facility and Test Method

Descriptive Note:

Doctoral thesis

Corporate Author:

AIR FORCE INSTITUTE OF TECHNOLOGY WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT

Personal Author(s):

• Winder, Sheen L.

Report Date:

2015-03-26

Pagination or Media Count:

261.0

Abstract:

With a melting point in excess of 3000 deg C and a high density, ultra-high temperature ceramics UHTCs are a candidate material for hypersonic flight vehicles, atmospheric re-entry vehicles, and rocket propulsion systems. When ceramics are under consideration as a structural material, creep is an important design criterion and a life-limiting condition. However, the characterization of mechanical behavior at temperatures in excess of 1300 deg C has many challenges to overcome. Of utmost importance is the selection of materials for test fixtures. Materials selected must maintain their structural integrity, not cause chemical degradation of the test material, and not interfere with the acquisition of data at required temperatures in extreme environments over long durations. In this work, the thermo-chemical compatibility of hafnium diboride HfB2 UHTC with other high temperature materials was investigated. The findings enabled the development and construction of a mechanical testing facility capable of reaching 1700 deg C in air. Platinum foil proved unstable in the presence of HfB2 at 1500 deg C, while yttrium aluminum garnet and alumina were demonstrated to successfully perform as test fixture materials inside the test chamber. The results of this research represent a significant contribution towards the use of UHTCs in extreme environments associated with hypersonic flight and atmospheric re-entry.

Descriptors:

• *CERAMIC MATERIALS
• *HYPERSONIC FLIGHT
• *HYPERSONIC VEHICLES
• *REENTRY VEHICLES
• *ROCKET PROPULSION
• COMPATIBILITY
• CREEP
• HIGH DENSITY
• HIGH TEMPERATURE
• MECHANICAL PROPERTIES
• MELTING POINT
• OXIDATION
• PLATINUM
• SINGLE CRYSTALS
• STRUCTURAL INTEGRITY
• TEST METHODS
• THESES
• YTTRIUM ALUMINUM GARNET

Subject Categories:

• Ceramics, Refractories and Glass

Distribution Statement:

APPROVED FOR PUBLIC RELEASE