关键词: 激光熔丝增材制造, 超声微锻造, 热-结构耦合, 残余应力, TC4钛合金

Abstract: Laser-wire additive manufacturing technology can greatly improve manufacturing efficiency， but the complex residual stress is existent inside the part and leads to poor internal defects. To solve these problems， ultrasonic micro-forging and rolling assistant technology were adopted， that the surface of the part is stroked with high-frequency vibration， which causes the surface of metallic material to plastically deform and the stress changes from the tensile stress to compression stress. Taking the TC4 as study object， the numerical analysis of thermal-structural coupling of laser fuse process is implemented by utilizing ANSYS， and the ultrasonic rolling micro-forging is applied to study the stress field before and after micro-forging. The results show that the stress distribution of laser fuse cladding layer， namely the stress distribution becomes more uniform， the tensile stress decreases and even transfers to compressive stress， which can effectively restrain the formation of internal defects.

Key words: laser-wire additive manufacturing, ultrasonic micro-forging, thermal-structure coupling, residual stress, TC4 titanium alloy