Engineers working for the Air Force have developed transparent ceramic armor (aluminum oxynitride or ALON) that provides better ballistic protection at less than half the weight and thickness of traditional glass laminates. This provides soldiers and civilians with superior protection for both air and ground vehicles. The development was based on the growing need in the Defense Dept. for transparent armor for personnel protection and infrared windows for reconnaissance applications.
The Army UH-60M helicopter platforms use transparent armor systems mounted behind the pilots.
ALON is a transparent ceramic material composed of aluminum, oxygen, and nitrogen. It begins as a powder that is formed into shapes and made transparent by applying high temperatures and pressure. The Air Force has been working with this material since 2006. Prior to the current breakthroughs the largest ALON windows were limited to 2.8 square feet. ALON is now made routinely in sizes up to eight square feet by a small business, Surmet Corp. Scaling up is performed incrementally, due to the complex manufacturing steps that must be used. The Air Force is getting closer to providing a commodity material for government purposes.
Transparent armor is currently used on U.S. Army Blackhawk and Chinook helicopters. ALON’s excellent durability and impact resistance have also made it of interest to NASA for windows on the International Space Station.
A projectile exit point is shown in the ballistic glass (left). The aluminum oxynitride transparent ceramic armor is shown (right) with a bulge and no exit from the projectile.
The next step in protecting warfighters is creating a curved window. Curved ALON will be attempted, but it may take the use of different materials.
As longtime Trekkies will tell you, ALON was used to create a giant aquarium way back in 1986’s “Star Trek IV: The Voyage Home.” More recently, it was also used in “Jurassic World” to build a protective bubble vehicle.