Characterization of Compressive Creep Behavior of Oxide/Oxide Composite With Monazite Coating at Elevated Temperature

<p>Ceramic-matrix composites (CMCs) capable of maintaining excellent strength and fracture toughness at high temperatures are prime candidate materials for aerospace turbine engine applications. In these applications CMCs will be subjected to mechanical loading in complex environments. Before ceramic matrix composites can be used in high-temperature aerospace engine applications their structural integrity and long-term environmental durability must be assured. This research investigated compressive stress-strain and compressive creep behavior of the N610/M/A at 900 and 1100 -C. The composite consists of a porous alumina matrix reinforced with NextelTM610 fibers coated with monazite in a symmetric cross-ply (0-/90-/0-/90-)s orientation. The addition of monazite coating resulted in loss of compressive strength at both 900 and 1100 -C. Compressive creep behavior was examined at 900 and 1100-C for creep stresses ranging from 50 to 95 MPa. At 900 -C both monazite containing and control specimens produced creep strains d 0.05%. Conversely at 1100 -C creep strains approaced 9%. Creep strain rates were on the order of 10-7 s-1. Creep run-out defined as 100 h at creep stress was achieved in all tests. Composite microstructure as well as damage and failure mechanisms were investigated. Furthermore effects of variation in microstructure on mechanical response were examined. While differences in processing and consequently the composite microstructure did not have a significant effect on tensile response of the CMC effects on the compressive properties were dramatic.</p><p>This work has been selected by scholars as being culturally important and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact and remains as true to the original work as possible. Therefore you will see the original copyright references library stamps (as most of these works have been housed in our most important libraries around the world) and other notations in the work.</p><p>This work is in the public domain in the United States of America and possibly other nations. Within the United States you may freely copy and distribute this work as no entity (individual or corporate) has a copyright on the body of the work.</p><p>As a reproduction of a historical artifact this work may contain missing or blurred pages poor pictures errant marks etc. Scholars believe and we concur that this work is important enough to be preserved reproduced and made generally available to the public. We appreciate your support of the preservation process and thank you for being an important part of keeping this knowledge alive and relevant.</p>