High-throughput explosive welding of multimetallic coatings on Mg–Li alloys: Interfacial mechanisms and performance insights

Magnesium–lithium (Mg–Li) alloys are promising ultra-light structural materials but suffer from low surface hardness and poor corrosion resistance. Here we develop a high-throughput explosive welding (HT-EXW) configuration that joins many dissimilar metals to a single LZ91 Mg–Li plate in spatially separated regions during one detonation, enabling parallel weldability evaluation under identical loading conditions. A layer of ANFO explosive (∼40 mm, detonation velocity ≈ 2300 m·s -1 ), Ti confinement plates and a 2 mm stand-off distance are used to bond sixteen commercially pure metal foils (∼0.1 mm thick), spanning a wide range of melting temperatures and thermophysical properties. Cross-sectional observations reveal a transition from nearly planar Mg–Li/metal interfaces for high-melting-point flyers to pronounced wavy and locally melted interfaces for low-melting-point flyers. EBSD and EDS analyses of a representative Ta/LZ91 joint show equiaxed Ta grains with interfacial refinement and a thin (∼5 μm) asymmetric mixing layer, indicating a mixed solid-state and local-melt bonding mechanism. Quantitative analysis of the melting zones demonstrates that the atomic ratio of flyer main element to base main element (FME/BME) decreases monotonically with flyer melting temperature and can be described by an inverse-square relation k/(FMT) 2 . Microhardness measurements show that the minimum joint-region hardness remains above ∼75% of the original flyer hardness, and most joints are harder than the Mg–Li substrate. Supplementary EBSD results on the Ti/Ti composite plate reveal a shock-induced gradient microstructure, implying near-interface strengthening in the confinement plates. These findings establish HT-EXW as a practical tool for high-throughput screening and mechanistic study of individual metal/Mg–Li explosive welds.