Studies on microstructure and properties of TiB2–Al3Ti ceramic particles reinforced spray-formed 7055 aluminum alloy fusion welded joints

Due to the brittle weld joints and worsening hot cracking tendency of spray-formed (SF) 7055 aluminum alloy, they are regarded as un-weldable. In this study, TiB2–Al3Ti/7055 (MA) aluminum matrix composites manufactured by the master alloy method were used to connect SF 7055 aluminum alloy. In the as-weld state, ceramic particles refine α-Al grains in weld metal (WM) and reduce the hot cracking tendency of weld joints. The tensile properties of weld joints increased from 240 ± 5 MPa, 1.4 ± 0.24% (7055) to 284 ± 5 MPa, 4.0 ± 0.35% (MA). In the heat treatment states (T6, T76, and RRA), the mechanical properties and corrosion resistance of MA-WM are superior to 7055-WM. The tensile strength of MA-T6 (485 ± 20 MPa, 3.10 ± 0.23%) is the best of the three heat treatment states, while the corrosion resistance of MA-T76 is the best. MA-RRA gains mechanical properties similar to MA-T6 and corrosion resistance close to MA-T76.