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U.S. Department of Energy
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Influence of fiber lay-up sequence on mechanical properties of SiC(f)/SiC composites

Conference ·
OSTI ID:568116
; ;  [1]
  1. Argonne National Lab., IL (United States)

Mechanical properties of Nicalon-fiber-reinforced silicon carbide matrix composites with two different fiber lay-up sequences (0{degrees}/40{degrees}/60{degrees} and 0{degrees}/45{degrees}) were evaluated at various temperatures ranging from ambient to 1300{degrees}C. Composites with 0{degrees}/40{degrees}/60{degrees} fiber lay-up sequence showed a higher average first matrix cracking stress than that of 0{degrees}/45{degrees} composites. The measured room-temperature ultimate strength of the 0{degrees}/40{degrees}60{degrees} composites was 300 MPa, compared to 180 MPa for the 0{degrees}/45{degrees} composites. These measured ultimate strengths were correlated to the predictions made with an analytical model and to in-situ fiber strength characteristics. The large difference in room-temperature ultimate strengths between the two sets of composites is attributed to the relative contributions of the off-axis fibers to the load-bearing capacity of each composite. Up to 1200{degrees}C, ultimate strength and work-of-fracture in each set of composites increased, but then declined above 1300{degrees}C. The decreases were correlated to in-situ Nicalon fiber strength and fiber/matrix interface degradation.

OSTI ID:
568116
Report Number(s):
CONF-960106--
Country of Publication:
United States
Language:
English