Fig. 1. 2024 aluminum alloy powder. (a) SEM image; (b) size distribution

Fig. 2. Single-channel morphology and metallographic contrast of LMD alloy

Fig. 3. Microstructural comparison of 2024 alloy obtained by LMD. (a) P＝1800W, V＝360 mm/s, D＝1.6 mm; (b) P＝1800 W, V＝480 mm/s, D＝1.8 mm; (c) P＝1800 W, V＝600 mm/s, D＝2.0 mm; (d) P＝2000 W, V＝360 mm/s, D＝1.6 mm; (e) P＝2000 W, V＝480 mm/s, D＝1.8 mm; (f) P＝2000 W, V＝600 mm/s, D＝2.0 mm; (g) P＝2200 W, V＝360 mm/s, D＝1.6 mm; (h) P＝2200 W, V＝4800 mm/s, D＝1.8 mm; (i) P＝2200 W, V＝600 mm/s, D＝2.0 mm

Fig. 4. Microstructures after LMD-stirring

Fig. 5. Cross-sectional microstructures of LMD-stirring-deposition alloy

Fig. 6. Microstructures of aging alloy. (a) Substrate; (b) top area after secondary deposition; (c) interface after deposition and stirring; (d) stirring area

Fig. 7. Microhardnesses of 2024 alloy along deposition direction. (a) Schematic of hardness test; (b) micrograph of hardness test; (c) hardness distributions after LMD＋stirring heat treatment; (d) hardness distributions after LMD＋stirring＋ LMD heat treatment