Fracture Studies of Brittle Materials: Part II. Chemomechanical Effects of Hydrogen on Soda-Lime Glass and Silicon

摘要

The effects of hydrogen and other environments on the fracture strength of soda-lime glass and silicon have been investigated using ultrahigh vacuum techniques for precise environmental control. Samples were scribed, soaked, and fractured in vacuum, water vapor, and hydrogen environments. Four-point flexure strength measurements, exoelectron emission, constant moment double cantilever beam slow crack propagation, and previous acoustic emission drilling/grinding experiments all show that hydrogen affects crack propagation. In controlled environments, increases in strength of as much as 235% of the vacuum strength were observed for vacuum scribed-hydrogen soaked soda-lime glass. The separate and synergistic effects of residual stress, hydrogen, water vapor, and air environments are discussed in terms of a hypothesis involving chemical reactions at the surface, residual stress relief in active environments, and stresses arising from diffusional concentration gradients. (ERA citation 08:005694)