Wire-based friction stir additive manufacturing enables enhanced interlayer bonding in aluminum-matrix composites
Shuming Sun, Xiangchen Meng, Yuming Xie, Jinqi Wang, Xiaotian Ma, Naijie Wang, Xianfeng Li, Yongxian Huang
Abstract
Solid-state additive manufacturing of aluminum matrix composites avoids reinforcement agglomeration in melting-based processes, but weak interlayer bonding remains a critical constraint. Wire-based friction stir additive manufacturing (W-FSAM) was proposed to address these challenges. A novel eccentric single-pin screw arbor was propitious to achieve defect-free interlayer bonding by enabling thorough vertical flow-mixing of deposited material. The W-FSAM composite developed equiaxed grains with an average diameter of 1.18 μm through dynamic recrystallization combined with pinning of TiB 2 nanoparticles. The TiB₂ particles were uniformly dispersed by intensified stirring flow of the eccentric pin tool. Partial penetration of the stir pin into prior deposition layer improves interlayer material flow and mixing, strengthening metallurgical bonding. The exceptional mechanical isotropy, exhibiting tensile strengths and elongations of 402.7 ± 14.3 MPa with 13.2 ± 0.5 % (longitudinal direction), 408.8 ± 12.3 MPa with 13.4 ± 0.7 % (transverse direction), and 391.2 ± 18.6 MPa with 12.4 ± 0.9 % (build direction) were achieved. W-FSAM demonstrates significant potential for aluminum matrix composites in aerospace applications requiring high strength-to-weight ratios and quasi-isotropic performance.