|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Ultrafine-grained and Heterostructured Materials (UFGH XII)
||Deformation Mechanisms of Laser Rapid Solidified Al–Si Heterostructures
||Bingqiang Wei, Wenqian Wu, Amit Misra, Jian Wang
|On-Site Speaker (Planned)
Using laser rapid solidification (LRS) techniques, as-cast Al–20wt.% Si alloys was modified to achieve a heterogeneous microstructure which was consisted of micro-scale Al dendrites (1-2 Ám) and ultrafine Al-Si eutectic with Si nanofibers (40-50 nm). In-situ SEM tension tests revealed that the heterostructured Al-Si alloys exhibit high strength (>600 MPa), good ductility (>10%) and high strain hardening rate. These superior mechanical properties were ascribed to the strong synergistic effect between soft Al dendrites and hard Al-Si eutectic structure. Plastic deformation commences in soft Al dendrites through dislocations, and high strain hardening rate develops associated with dislocations pileup in soft Al grain. With the increase in flow strength, ultrafine Al-Si eutectic plastically deforms by dislocations in Al matrix. Si nanofibers act as strong barriers for dislocations motion and sites for dislocations accumulation, developing high incompatibility of plastic deformation and leading to fracture of Si nanofibers.
||Aluminum, Mechanical Properties, Additive Manufacturing