Abstract: Ultra-high strength (over 600 MPa) Al-Zn-Mg-Cu alloys processed via wire arc directed energy deposition suffers from high porosity and extremely low ductility, severely hindering their applications. This study presents an innovative particle modification strategy to overcome these limitations. By synergistically introducing TiB₂ particles with Sc and Zr elements, composite particles with a unique TiB₂ core/Al3(Sc,Zr) shell structure are formed, significantly reducing the lattice mismatch between TiB₂ and Al matrix while enhancing interfacial coherence. These TiB₂/Al₃(Sc,Zr) particles served multiple critical functions: not only refine grain size by acting as nucleation sites, but also provide pore nucleation sites to facilitate pore nucleation and floating, thereby significantly reducing pore size and porosity. The maximum pore size significantly decreased from 532.2 μm to 99.3 μm and the porosity decreased from 0.55% to 0.19%. Besides, the WA-DED TiB2/7B55 alloy exhibits excellent mechanical properties, with a tensile strength of up to 640 MPa and significantly improved ductility at room temperature (elongation increased by approximately 64%, from 6.6% to 10.8%). Remarkably, at a high temperature of 200 ℃, TiB₂/Al₃(Sc,Zr) particles distributed along the grain boundaries will act as a supporting skeleton to hinder the migration and sliding of the grain boundaries. This led to superior high temperature tensile properties, comparable to most commercial heat-resistant aluminum alloys. This work demonstrates that the design of TiB₂/Al₃(Sc,Zr) core-shell particles provides a highly effective approach to simultaneously enhance strength, ductility, and high temperature properties, meeting the requirements for their application in various high demand fields.