Material Technology for Thermal Management of Gun Barrels

Mortar tube erosion is the result of thermal and chemical interactions between the tube materials and the propellant combustion gases. A well-engineered material system could manage the thermal conditions inside the tube, reduce the erosion, and decreasethe tube weight. TPL proposes to use explosive cladding to combine the best of both erosion-resistant refractory metals and the mechanical strength of a transition metal alloy. A refractory metal liner clad to a titanium jacket would reduce erosion and decrease weight byup to 40%. TPL has shown that Bushmaster barrels clad with tantalum have 350% longer life when using M919 ammunition - a high temperature cartridge. TPL's innovation offers the Army future capability with the use of more energetic propellant. The approach to the program utilizes both modeling and experimental verification. TPL will use a heat flow model to analytically test and refine concepts for a materials-based design. A prototype will be fabricated and heat transfer tests will beconducted. TPL's Energetic Materials Research Development and Engineering Department is a self contained entity. The company maintains a formulation laboratory, a machine shop, and a test facility. The company is licensed to use explosives with the Bureau ofAlcohol, Tobacco and Firearms. TPL's approach will benefit the Army on two levels. First, from an operational level, the clad tubes will have a greater life expectancies and the tubes should also have the capability of using more energetic propellants. Secondly, TPL plans tointegrate a commercial effort concurrent to the development of the mortar tubes with the goal of producing an item for the private sector. When the two efforts conclude in the Phase II program, TPL should be able to offer the private sector a product ofwhich the mortar tubes are a specialty item. This plan should reduce costs to the Army.