High　strength　Al-Cu　alloys　are　of　great　interest　for　processing　using　additive　manufacturing　for　aerospace　applications.　In　this　study,　a　Ti-modified　Al-Cu　alloy　was　successfully　processed　by　in-situ　alloying　laser　powder　bed　fusion　(LPBF).　The　relationship　between　the　volumetric　energy　density　(VED)　and　the　densification　of　a　Ti-modified　and　unmodified　Al-Cu　alloy　was　investigated.　The　results　showed　that　a　high-density,　crack-free　Al-Cu　alloy　can　be　achieved　with　the　addition　of　Ti.　Hot　cracks　occurred　along　the　coarse　columnar　grains　in　the　unmodified　Al-Cu　alloy　due　to　the　severe　stress　concentrations　arising　during　the　LPBF　process.　The　elimination　of　hot　cracks　was　attributed　to　the　decrease　of　grain　size　and　the　change　of　grain　morphology　from　columnar　to　equiaxed　with　the　Ti　addition.　The　tensile　properties　of　the　Ti-modified　Al-Cu　alloy　were　significantly　improved　with　a　yield　strength　of　200　MPa,　an　ultimate　strength　of　289　MPa,　and　an　elongation　to　failure　of　8　%.　The　strengthening　mechanisms　including　grain　refinement　strengthening,　solid　solution　strengthening　and　second　phase　strengthening　were　quantified　and　the　fracture　mechanism　was　discussed.　The　tribological　results　showed　that　a　low　wear　rate　of　3.03　×　10−4　mm3　N−1　m−1　was　achieved　in　the　alloy　with　Ti　modification,　while　unmodified　alloy　showed　a　poor　wear　resistance.　The　study　demonstrates　a　novel　method　to　develop　advanced　Al-Cu　alloy　with　high　density,　strength　and　tribological　resistance　by　in-situ　alloying　LPBF.　©　2023　Elsevier　B.V.