Intellectual Property Office

Non-Confidential Disclosures

“Crack Arrest In Brittle Materials Using Residual Stresses”

PSU Invention Disclosure No. 1731

Inventors:

D.J. Green, et al.

Invention description:

The brittle fracture behavior of glasses and ceramics makes the strength of these materials strongly dependent on the size and location of stress concentrating flaws. Surface flaws formed during contact damage reduce strength resulting in the failure of glasses and ceramics usually in an unstable and catastrophic way. This invention uses residual compressive stresses to induce crack stabilization - a novel alternative means of enhancing mechanical reliability. The inventors have demonstrated a method to use residual surface compression to achieve the following:

Strengthening of the materials
Significant reduction in strength variability
Strength insensitivity to initial flaw size
Improved mechanical reliability

Brittle materials, such as glass, demonstrate some degree of fail-safe behavior after treatment. Treated materials undergo multiple cracking. A crack forms in the surface, but then arrests. This is followed by the formation of other cracks. Such behavior is extremely unusual and can be exploited in many ceramics and glass applications.

Contact:

Richard M. Weyer
Sr. Technology Licensing Officer
Intellectual Property Office
The Pennsylvania State University
113 Technology Center
University Park, PA 16802
Phone: (814) 865-6279
Fax: (814) 865-3591
E-mail: rmw4@psu.edu