Dimensional, tensile strength and fracture surface characterizations were carried out for a particular batch (51 samples) of unirradiated Hi-Nicalon™ SiC fiber. This batch of SiC fibers is included in the radiation test matrix as part of the JUPITER 12J and 14J experiments. In general, filaments of Hi-Nicalon™ fiber with larger cross-sectional areas (equivalent diameters) had lower strengths than filaments with smaller cross-sectional areas. During tensile tests at room temperature, fracture originated at critical flaws that typically consisted of internal pores or carbonaceous inclusions. Well-demarcated mirror and hackle regions usually surrounded the critical flaws. With a few exceptions, the critical flaw size (ac) was linearly related to the mirror size (rm) by ac » 0.33rm. From fracture mechanics principles, values for the average mirror constant (Am) and effective fracture toughness for this batch of Hi-NicalonÔ fiber were estimated to be 2.99 ± 0.33 and 1.1 ± 0.2 MPa m1/2, respectively.
Revised: July 27, 2010 |
Published: June 30, 2000
Citation
Youngblood G.E., C.A. Lewinsohn, R.H. Jones, and A. Kohyama. 2000.TENSILE STRENGTH AND FRACTURE SURFACE CHARACTERIZATION OF HI-NICALONTM SIC FIBERS. In Fusion Materials Semi-Annual Progress Report Ending June 30, 2000, edited by Berk, S.E. 96-97. Washington Dc:Department of Energy, Office of Fusion Energy Sciences.PNNL-SA-31887.