Thermal, Metallurgical and Mechanical Determinants of Laminar Nickel/Aluminum Dissimilar Alloys during Laser-material Interaction Part I: Nickel-based Superalloy

To develop in-depth understanding of metallurgical phenomena for completeness, mechanical heterogeneity is kinetically and thermodynamically explained by thorough microstructure characterization engineering materials, e.g. polycrystalline nickel-based superalloy, alleviation weldability-related problems during laser-induced keyhole fabrication. Because nonequilibrium solidification behavior inside weld pool, finer γ phase dendrite substructure confined to partition-resistant bottom part, coarser crystallography-independently circumscribed at partition-vulnerable neck transition region full penetration weld, thus lack homogeneity. Abundance segregation-driven eutectic or intermetallic in the interdendrite area throughout essentially attributable conditions, morphologically increases susceptibility properties deterioration. As a result instability, Niobium-aided Laves/γ reaction vicinity interstices terminal stage contributes severe boundaries brittleness, impairs properties, which consistent with metallography fractography results, more deleterious weldability, since solute redistribution supersaturation adversely exacerbate segregation residual liquid, especially asymmetric pool shape. There inverse parabolic relationship between secondary arm spacing partition coefficient, when location varies from nail-shaped upper site site. Chemical, microstructural heterogeneities are geometrically favorable curvature-related region. In addition, mechanism thermal, inhomogeneities, attributed shape, consequently proposed. Untoward phenomena, such as brittle Niobium-rich phases mitigate strength, ductility toughness weld. order macroscopically microscopically satisfy superior requirement, chemistry high quality metallurgically controlled. Fruitful information data further support reasonable explanations. It imperative progressively advance welding metallurgy, weldability fabricability intricate shape defects minimization, suppress through viable design control laser processing, simultaneously.