Studies on microstructure and properties of TiB2–Al3Ti ceramic particles reinforced spray-formed 7055 aluminum alloy fusion welded joints
Yun Cheng, Yunxuan Hu, Junhua Xu, Lihua Yu, Ting Huang, Hao Zhang
Abstract
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.