Date of Award

3-21-2019

Document Type

Thesis

Degree Name

Master of Science in Materials Science

Department

Department of Aeronautics and Astronautics

First Advisor

Marina B. Ruggles-Wrenn, PhD

Abstract

Interlaminar shear properties of a high temperature polymer matrix composite (HTPMC) and a ceramic matrix composite (CMC) were evaluated at elevated tempera- ture. Two variants of the HTPMC were studied. Both consisted of a high-temperature polyimide (AFR-PE-4) matrix reinforced with Astroquartz-III pre-impregnated glass fabric woven in an eight-harness-satin weave. The first HTPMC variant also contained stainless steel foil at the midplane, while the second HTPMC variant did not. The interlaminar shear strength (ILSS) of both variants of the HTPMC was evaluated at 204°C in laboratory air. The addition of the stainless steel foil resulted in significant loss of ILSS for the HTPMC. The CMC studied in this work was fabricated via chemical vapor infiltration. The CMC had an oxidation-inhibited matrix consisting of alternating layers of SiC and B4C and was reinforced with Hi-NicalonTM fibers woven in a five-harness-satin weave. Fiber preforms had pyrolytic carbon coating and boron carbide overlay applied. The ILSS of the CMC was measured at 1300°C in laboratory air. Additionally, creep performance in interlaminar shear of the CMC was evaluated at 1300°C in air and in steam. The creep behavior was assessed for interlaminar shear stresses varying from 12 MPa to 20 MPa in air and in steam. In air and in steam, creep run-out of 100 h was achieved at 13 MPa. Both primary and secondary creep regimes were noted in all tests. Presence of steam had little effect on creep performance. The retained properties of the specimens that attained run-out were characterized. Pre- and post-test composite microstructures were examined to evaluate damage and failure mechanisms.

AFIT Designator

AFIT-ENY-MS-19-M-250

DTIC Accession Number

AD1076418

Download

Share

COinS