Strength and fractographic analysis of chalcogenide As–S–Se and Ge–As–Se–Te glass fibers

The strengths and Weibull parameters of chalcogenide As–S–Se and Ge–As–Se–Te glass fibers were measured, and the fiber fracture surfaces examined. The sulfide (As–S–Se) fibers have a mean strength of 545 MPa, characteristic strength of 567 MPa, and Weibull slope, m, of 8.5. The weaker telluride (Ge–As–Se–Te) fibers have a mean strength of 427 MPa, characteristic strength of 441 MPa, and a Weibull slope of 11. Fractographic analysis indicates the sources of failure in these glass fibers are inclusions, microbubbles and microcracks. Fracture mirror measurements enabled estimations of fracture toughness and mean critical flaw sizes. The lower strength of the Ge–As–Se–Te glass fibers was determined to be a consequence of a more severe flaw population.