SEDL / STP / STP1332-EB / STP14960S

New Perspectives on the Fracture of Nicalon Fibers

Taylor, ST
Graduate Student, University of California, Berkeley, CA

Zhu, YT
Technical Staff Member, Los Alamos National Laboratory, Los Alamos, NM

Blumenthal, WR
Technical Staff Member, Los Alamos National Laboratory, Los Alamos, NM

Stout, MG
Technical Staff Member, Los Alamos National Laboratory, Los Alamos, NM

Butt, DP
Technical Staff Member, Los Alamos National Laboratory, Los Alamos, NM

Lowex, TC
Technical Staff Member, Los Alamos National Laboratory, Los Alamos, NM

Pages: 11    Published: Jan 1999

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Abstract

Experimental studies have been conducted to examine the strength and fracture behavior of monofilament Nicalon™ SiC fibers ranging in diameter from 8 to 22 μm. The effects of varying fiber diameter, flaw location and flaw population on the tensile behavior of individual fibers were investigated using fractography. Results indicate that variations in fiber diameter influence the apparent fiber fracture toughness (K^1c), with higher K^1c values observed for decreasing fiber diameters. Observations also suggest that the location of the critical flaw may play a role in the fracture of Nicalon fibers. In addition to surface flaws, three distinct internal flaw populations are seen to cause fracture in Nicalon fibers.