超声微锻造辅助激光熔丝增材制造数值模拟研究

激光熔丝增材制造技术能大大提高制造效率，但制件存在复杂的残余应力，导致制件内部缺陷多.为了解决这些问题，将超声微锻造与滚压相结合对制件表面进行高频率击打，使金属表层产生塑性变形，将原有的拉应力转变成压应力.以TC4为研究对象，利用ANSYS对激光熔丝过程进行热-结构耦合数值模拟，并施加超声滚压微锻造，分析微锻造前后应力场的变化情况.研究结果表明:激光熔丝熔覆层应力分布更加均匀，拉应力减小，甚至转化为压应力，有效地抑制制件内部缺陷的形成.

Numerical Simulation Research of Ultrasonic Micro-forging Assisted Laser-Wire Additive Manufacturing

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.