Influence of micro-rolling on the strength and ductility of plasma-arc additively manufactured Ti-6Al-4V alloys

作者：Pan, Ziqin; Zhang, Haiou; Song, Xinli^*; Wang, Guilan; Wu, Chuandong^*; Liu, XinWang

来源：Journal of Materials Research and Technology-JMR&T, 2022, 21: 465-473.

DOI：10.1016/j.jmrt.2022.09.035

• Plasma arc additive manufacturing
• Micro -rolling
• Ti-6Al-4V alloy
• Defects
• Basket -weave microstructure
• Strength and ductility

The aim of this study was to reduce the number of defects, refine the grain size, and improve the mechanical properties of Ti-6Al-4V. We investigated the effect of interpass micro-rolling on the microstructures and mechanical properties of Ti-6Al-4V alloys produced via plasma arc additive manufacturing (PAAM). The non-rolled plasma-arc additively manufactured (PAAMed) sample exhibited coarse columnar crystals, basket -weave microstructures, and Widmanstaeurotten structures, while the interpass-micro-rolled PAAMed sample exhibited fine equiaxed crystals and basket-weave microstructures. Interpass micro-rolling could significantly reduce the number density and size of defects during PAAM, and the rolled samples exhibited lower mechanical property anisotropy than the non-rolled samples. Moreover, the rolled sample exhibited a higher yield strength (-797.66 and 793.45 MPa), tensile strength (-939.73 and 935.71 MPa), and elongation (-12.83% and 14.73%) in the X-and Z-directions than the unrolled sample. These enhanced mechanical properties can be attributed to aGB fragmentation, grain boundary strength-ening, dislocation strengthening, and a low crack density. The micro-cracks preferentially nucleated around defects in the non-rolled sample, resulting in high crack and defect densities.

• 单位
  华中科技大学