5.1 Properties determined by this test method are useful in the evaluation of new fibers at the research and development levels. Fibers with diameters up to 250 × 10^-6 m are covered by this test method. Very short fibers (including whiskers) call for specialized test techniques (1)3 and are not covered by this test method. This test method may also be useful in the initial screening of candidate fibers for applications in polymer, metal or ceramic matrix composites, and quality control purposes. Because of their nature, ceramic fibers do not have a unique strength, but rather, a distribution of strengths. In most cases when the strength of the fibers is controlled by one population of flaws, the distribution of fiber strengths can be described using a two-parameter Weibull distribution, although other distributions have also been suggested (2,3). This test method constitutes a methodology to obtain the strength of a single fiber. For the purpose of determining the parameters of the distribution of fiber strengths it is recommended to follow this test method in conjunction with Practice C1239.

1.1 This test method covers the preparation, mounting, and testing of single fibers (obtained either from a fiber bundle or a spool) for the determination of tensile strength and Young's modulus at ambient temperature. Advanced ceramic, glass, carbon and other fibers are covered by this test standard.

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.3 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.