在Ti-6Al-4V合金锻造成形双态组织基材上采用激光立体成形方法(送粉式激光增材制造)沉积块体试样，研究了不同线能量密度输入下基材与增材结合区的微观组织特征及形成机制。结果表明，结合区内不同高度部位由于热源影响程度存在差异，形成了从下到上的非均匀组织。其中下部区域由于峰值温度较低，仍保持初始双态组织形貌，但发生一定粗化；中部区域随着温度升高以及保温时间延长，形成等轴α相、层片α相及大量次生α相的混合组织；而上方靠近增材区的峰值温度超过β相转变温度，完全转变为由层片α相形成的魏氏体组织，并伴随着由于元素扩散不充分而形成的阴影结构。对包含基材区和增材区的结合试样进行拉伸测试发现，在设定的能量密度范围内，断裂位置均远离结合区，表明增材区与基材区结合良好，结合区强度超过基材区及增材区强度。此外，对比不同能量密度复合制造Ti-6Al-4V试样的拉伸测试结果发现，线能量密度为100 J/mm时，结合区以及增材区α相特征尺寸较小，复合制造试样的屈服强度和抗拉强度最大。随线能量密度的增大，复合制造试样屈服强度和抗拉强度均减小，而延伸率增加。

The forging-additive hybrid manufacturing technology combines the advantages of traditional manufacturing in terms of efficiency and cost with the refined, flexible, and rapid prototyping characteristics of additive manufacturing. It provides an effective solution for efficient forming of large components. The bonding zone between the wrought-substrate and laser-deposition zones is the fundamental key in the properties of the entire component. In this study, laser solid forming (a powder-feeding laser additive manufacturing technology) was used to deposit bulk samples on a wrought Ti-6Al-4V substrate that contained a bi-modal microstructure. The microstructure in the bonding zone between the substrate and laser-deposition zones under different inputs of linear energy density were studied. The results show that the microstructure in the bonding zone varied from the bottom to the top due to the different influence extents of the heat source. Because of the lower peak temperature, the bi-modal microstructure at the bottom of the bonding zone still retained the initial morphology but contained a certain degree of coarsening. A mixed structure that contained equiaxed α, lamellar α, and a large number of secondary α in the middle of the bonding zone occurred with the increase in temperature and prolonging of the holding time. Meanwhile, the peak temperature of the upper part exceeded the β-phase transition temperature, which exhibited a Widmanstätten structure consisting of lamellar α and the so-called ghost area that was formed due to insufficient element diffusion. In the tensile tests, the fracture position of all bonding samples fabricated with various linear energy densities were very far from the bonding zone, indicating a better strength of the bonding zone than that of the wrought substrate and laser-deposition part. In addition, when the linear energy density was 100 J/mm, the yield and tensile strengths of the composite fabricated sample were larger than that with linear energy densities of 133 and 200 J/mm because the feature size of the α phase in the bonding and additive zones was smaller. Both the yield and tensile strengths of the hybrid fabricated specimen decreased with the increase in the linear energy density, whereas the elongation increased.