In-situ strengthening of AZ31 magnesium alloy by introducing TC4 particles during wire-arc directed energy deposition with simultaneous feeding of powder and wire

TC4 particles reinforced AZ31 composite was successfully prepared by innovatively using simultaneous feeding method of powder and wire in wire-arc directed energy deposition (WA-DED). The results indicated that TC4 particles are expected to be evenly distributed in the AZ31 matrix and the introduced TC4 particle content of 9%-33.43 wt% can be acquired by adjusting the turret speed (TS) of powder feeder. The coarse columnar grains in the AZ31 transforms into the equiaxed grains after adding TC4 particles. A large number of acicular/flake Mg-Al phase and partial granular Al-Mn phase are formed around TC4 particles. The excellent tensile properties with yield strength of 85.6 MPa, ultimate tensile strength of 195 MPa and tensile elongation of 7.1% are obtained at the TS of 5 rpm, the corresponding maximum improvement efficiency reaches up to 42.6%. The improved strength mainly derives from grain refinement strengthening and thermal mismatch strengthening.