Elimination of defects in laser metal deposited TiCp/Ti6Al4V composite by synchronous ultrasonic impact treatment

TiCp/Ti6Al4V composites produced by laser metal deposition (LMD) are usually characterized by internal defects and resultant deteriorated mechanical properties. In the present work, a synchronous ultrasonic impact treat-ment (UIT) was introduced during LMD of TiCp/Ti6Al4V composites. The effect of synchronous UIT on the defects was investigated. The defects in the LMDed composites are sub-spherical pores distributed in the inter-layer region. With the assistance of UIT, the maximum surface height difference reduces from 200.2 & PLUSMN; 0.5 & mu;m to 25 & PLUSMN; 0.5 & mu;m and the internal porosity decreases from 1.95% to 0.09%, which is attributed to inhibiting the nucleation of defects and increasing molten pool flow. This work may provide a solution to effectively reduce the defects in additively manufactured parts.