Development of 2139 Armor plate for defense applications

Aluminum armor solutions have been in existence for the past 60 years. Aluminum armor was developed and selected based on its lower density. Based on their ballistic characteristics alloys 5083-H131 and 7039-T64 were the preferred alloys for the armored vehicles. Recently new type of warfare emerged. Soldiers are increasingly engaged in urban warfare with multiple threats. Armor piercing rounds are fired at close distance and rocket propelled grenades are a weapon of choice. Beyond that, a new threat emerged affecting armored columns on the roadways and on the city streets. Emergence of Improvised Explosive Devices (IEDs), which detonate under the moving vehicle, forced Army to seek new solutions that would improve performance of aluminum armor alloys by adding blast protection. Aluminum producers responded by developing more advanced armor solutions. This article will highlight alloy 2139 (KEIKOR^TM 2139) which has been standardized in MIL-DTL 32341A. Alloy 2139 was developed for armor applications in the .500-4.000” thickness range. It is a high strength/toughness copper-magnesium-manganese-silver alloy with superior corrosion resistance (SCC) and ability to resist softening at elevated temperatures. It is produced in two discrete tempers: an AP/FSP resistant temper (T8) and a blast-resistant temper (T84). For a given armor thickness 2139 Armor plate offers 300-500 ft. /sec extra margin of safety for specific type of armor piercing threat. Due to its higher strength and toughness 2139-T84 experiences lower plastic deformation under a standardized blast test when compared to legacy 5083 armor. This provides higher survivability for the occupants of the armored personnel carrier.