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Windscreen repels armour-piercing bullets

发布时间:2019-02-28 06:06:09来源:未知点击:

By Will Knight A transparent material tough enough to withstand armour piercing rounds is being tested by the US Air Force. Aluminium oxynitride, known commercially as ALON, could replace the existing bullet-proof glass on military vehicles, which is heavier and less tough. “The substance itself is light years ahead of glass,” says Lieutenant Joseph La Monica, head of the transparent armour research project at the Air Force research laboratory in Ohio. ALON is a ceramic compound made from aluminium, oxygen and nitrogen, and has similar optical and structural properties to sapphire. While conventional bullet-proof glass is made from layers of laminated glass and polycarbonate, the new screen comprises an outer layer of ALON, a middle section of toughened glass and back sheet of polymer. During tests conducted at the University of Dayton Research Institute, also in Ohio, the material withstood armour-piercing rounds fired from a .30 calibre Russian M-44 sniper rifle and a .50 calibre Browning sniper rifle. It also withstood repeated strikes from .30 calibre armour-piercing bullets. Ordinary bullet-proof glass would need to be made far thicker by tens of centimetres to become equally robust. Further tests will determine how well the screen holds up to multiple impacts from larger calibre shells, as well as explosives. “It is impressive,” says Ronald Hoffman of the University of Dayton Research Institute, who ran the tests. He told New Scientist the material would most likely be used in vehicles such as military aircraft, where the weight of amour is crucial. The only drawback is that ALON is expensive to make. It costs up to $15 per square inch (2.5 centimetres squared) – three times more than normal bullet-proof glass. That is because the machinery required for fabrication is expensive and because the material must undergo intensive polishing before use. However,