Nano-technology for armor: hype, facts, and future

Over the past two decades, nanotechnology has offered the promise of revolutionary performance improvements over existing armor materials. During that time there was substantial effort and resources put into developing the material technology and supporting theories, with only limited emphasis placed on understanding the ballistic event, mechanisms that drive armor performance, and the dependent nature of the threat. As a result, this large investment in nanotechnology for armor has not produced improved performance on the ballistics testing range, and armor nanotechnologies have never been fielded. No matter what the platform, armor systems have several functions that they have to perform in order to function properly. In order to defeat a threat, armor systems are designed to: deform/deflect the threat; dissipate energy; and prevent residual debris penetration. To date there is no definitive answer as to what material properties drive the system behavior of these functions at high rates in response to a specific threat, making the adaptation of nanotechnology that much harder. However, these functions are now being considered with respect to the material system and armor mechanism being utilized, and nanotechnology is beginning to be shown as an effective means of improving performance. When looking at the materials being used today, there are examples of nanotechnology making inroads into today's latest systems. Nano-particles are being used to manipulate grain boundaries in both metals and ceramics to tailor performance. Composite materials are utilizing nanotechnology to enhance basic material properties and enhance the system level behaviors to high rate events. While the anticipated revolution never occurred, nanotechnology is beginning to be utilized as an enabler in the latest armor performance improvements.