An investigation on microstructures and mechanical properties of explosive cladded C103 niobium alloy over C263 nimonic alloy

Futuristic aerospace applications such as advanced turbojet and scramjet engines used in subsonic, supersonic, and trans-atmospheric flights require materials with ever-increasing temperature and load bearing capabilities for improved performance. The materials C103 niobium alloy and C263 nimonic alloy are widely employed in the manufacturing of scramjet engine components. Efforts to join these two materials by fusion welding process have revealed that they are metallurgically incompatible due to the extreme propensity to form brittle intermetallics. The possibility of interdicting interlayer is explored to overcome the formulation of intermetallics and the attempts have not yielded fruitful results. Explosive welding/cladding is one of the possible ways to join these materials, as it is a solid state joining process. The present work aims at studying structure-property correlations in an explosive weld of C103 niobium alloy and C263 nimonic alloy. Explosive welding was carried out taking both the materials in solution-annealed condition. Microstructural studies were carried out to evaluate the integrity of weld joint. Mechanical properties such as shear strength of weld interface was found to be superior and ram tensile strength was observed to be marginally inferior compared to the strength of weaker component of the weld joint. The micro-hardness was observed to be high at the bond interface on C263 nimonic alloy side. The three point bend tests were conducted on the weld joint in such a way that the cladding was subjected to tension, which has not shown any cracks at the interface. (C) 2014 Elsevier B.V. All rights reserved.