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Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

2019

Theses/Dissertations

Air Force Institute of Technology

Creep Tests

Articles 1 - 2 of 2

Full-Text Articles in Engineering

Creep Of Nextel 720/Alumina Ceramic Matrix Composite With Diamond-Drilled Effusion Holes At 1200°C In Air And In Steam, Megan L. Harkins Mar 2019

Creep Of Nextel 720/Alumina Ceramic Matrix Composite With Diamond-Drilled Effusion Holes At 1200°C In Air And In Steam, Megan L. Harkins

Theses and Dissertations

A recent study evaluated tensile stress-strain and tensile creep behavior of an oxide-oxide composite (Nextel™720/alumina) with laser-drilled effusion holes at 1200°C. It was determined that the presence of laser-drilled holes degraded the mechanical properties and performance of the CMC as a result of damage caused to the composite microstructure by the laser drilling process. Based on these results, the present effort sought to assess the effects of diamond-drilled holes on the mechanical behavior of this CMC. Tensile properties of the N720/A composite at 1200°C in laboratory air were unaffected by the presence of an array of 17 diamond-drilled effusion holes. …


Interlaminar Shear Performance Of High Temperature Composites, Tyler A. Wallis Mar 2019

Interlaminar Shear Performance Of High Temperature Composites, Tyler A. Wallis

Theses and Dissertations

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 …