Improving the Microstructural Stability of Nextel 610 Alumina Fibers Embedded in a Porous Alumina Matrix

$48.00 plus tax (Refund Policy)

Download / Buy Article:

Abstract:

Nextel 610 alumina fibers embedded in ceramic matrix composites (CMCs) with a pure alumina matrix show pronounced grain coarsening above 1350°C, which is not observed for stand-alone fibers under identical conditions. Moreover, a size gradient with small grains in the fiber center and large grains at the fiber periphery occurs. This can be explained in terms of the outward diffusion of silica traces, which normally reduces the fiber grain-boundary mobility. Silica outdiffusion and the related excessive grain growth can be suppressed if small amounts of silica are added to the alumina matrix in the green state. Aluminosilicate green compositions, on the other hand, result in a lower matrix sinterability, thus leading to inferior mechanical properties of the CMC. In this communication, we present a novel method to design a CMC that combines the key benefits of an alumina matrix (superior strength) with that of an aluminosilicate matrix (superior thermal stability). Small amounts of silica were added to a CMC starting material with a porous alumina matrix via the sol–gel technique. The silica post treatment effectively suppresses grain growth in fibers and matrix. Mechanical testing revealed significant strength retention in case of the silica-infiltrated CMC.

Document Type: Research Article

DOI: http://dx.doi.org/10.1111/j.1551-2916.2010.03658.x

Affiliations: German Aerospace Center, Institute of Materials Research, 51147 Köln, Germany

Publication date: July 1, 2010

Related content

Tools

Favourites

Share Content

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
X
Cookie Policy
ingentaconnect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more