MME Research Seminar: “The Mechanics of Gorilla Glass”

Gorilla Glass is a Corning Science and Technology brand of glass that bends and deforms without breaking under pressures that cause most other types of glass to crack or break. It is most commonly seen in the marketplace as a display cover for many mobile electronic devices such as cell phones, laptops, and other display applications. However, this glass does not rely on exceptional strength to avert scratches and other failures. As Dr. G. Scot Glaesemann, a Research Fellow at Corning, explained it, “The reason [Corning] invented Gorilla Glass was not because it was strong. It was because it was damage resistant.”

Gorilla Glass is able to do this because the makeup of the material has been altered in such a way that when a force acts upon the surface, the surface of the glass goes into compression while the center of the material enters a state of tension. This allows the material to behave more like a silica material and densify under stress instead of cracking or failing the way glass traditionally does. This combination of compression and tension creates a squeezing action when a force is applied. This action essentially squeezes cracks and scratches, preventing them from becoming a problem.

To demonstrate this, Dr. Glaesemann had a student attempt to crack a sample of soda-lime glass and Gorilla Glass. The student caused a fracture in the soda-lime glass with relative ease, but even with his full arm strength concentrated on a single point, he was unable to do more than bend the Gorilla Glass. According to Dr. Glaesemann, many people have tried to crack the glass in the same way and he has seen people break the skin on their hands in these attempts without fracturing the glass.

As Dr. Glaesemann explained, a large part of the process of inventing Gorilla Glass involved studying the why and how of the failure points of other glass products on the market. Most of the existing flaws they found that allowed for cracks and scratches were surface flaws, though there were some volume flaws in the samples as well. They also found that the prevalence of flaws in a sample of glass was partially dependant on who had handled the material most recently and how they had done so.

Corning researchers discovered that the best ways to improve glass strength is to reduce mechanical stresses at the crack tips. When they realized that for a lot of glasses, cracks form during unloading much more so than loading, they realized that a material which could densify in reaction to force would be highly useful, and thus Gorilla Glass was born.

When asked what it was that allowed the Corning team to come up with such an effective innovation so quickly, Dr. Glaesemann cited the ability to throw off traditional methods of invention that the company likes to use and the chance to instead blaze a new trail. “We actually have people [in the company] who do innovation,” Glaesemann said, “We didn’t invite any of them.”