Achieving superior strength-plasticity performance in laser powder bed fusion of AlSi10Mg via high-speed scanning remelting

Figures & data

Table 1. Deposition and HSSR process parameters.

Parameters	Scanning speed $v$(mm/s)	Laser power $P$(W)	Hatch spacing $h$ (μm)	Laser spot diameter $D$ (μm)	Layer thickness $n$ (μm)	Rotation angle $\phi$ (°)
LPBF	1600	340	100	80	30	67
HSSR	6000	400	50	80	–	67

Figure 1. Microstructure of the LPBF and LPBF-HSSR samples. (a–a₂) (i–i₂) Band contrast (BC), inverse pole figure (IPF), and GND distribution maps of the samples. (b) (j) PF images of (a₁) (i₁), respectively. (c–d) (k–l) Grain equivalent diameters and aspect ratios, respectively. (e–f) (m–n) SEM images and aspect ratios of the cellular sub-structures. (g–h) (o–p) SEM images and size distributions of the precipitated nano-particles.

Figure 2. Molten pool temperature field and solidification conditions. (a–b) Longitudinal cross-sections of the temperature field in the molten pool for LPBF and LPBF-HSSR specimens, respectively. (c–d) Comparative analysis of temperature gradient $G$, growth rate $R$, and cooling rate $\dot{T}$ at the isothermal melting interface for LPBF and LPBF-HSSR specimens. (e) Solidification maps illustrating $G$ and $R$ values under LPBF and HSSR conditions.

Figure 3. Uniaxial tensile properties. (a) Representative engineering stress–strain ($\sigma -ϵ$) curves. (b) Comparison of mechanical properties of the current LPBF-HSSR sample with those reported for LPBF [44–53], heat treatment (HT) [21–27], laser-directed energy deposition (LDED) [43,54], magnetic field (MF) application [28,29], remelting [30], composite materials [13–20], and high-strength aluminum alloy [7–12]. (c) True stress (${\sigma }_t$) and work-hardening rate ($\mathrm{\Theta }$) plotted against true strain (${ϵ}_t$) with an inset showing a detailed view. (d) Work-hardening exponent ($n$) values across different strain stages.

Table 2. Uniaxial tensile properties.

Samples	YS (MPa)	FS (MPa)	ETF (%)	E (GPa)
LPBF	219.6 ± 4.8	405.1 ± 1.8	10.5 ± 0.6	68.1 ± 2.8
LPBF-HSSR	279.5 ± 2.3	496.1 ± 5.8	21.4 ± 0.9	72.9 ± 4.6

Figure 4. LUR tensile testing and fracture analysis. (a) LUR tensile testing results for both samples. (b) Evolution of the ${\sigma }_{\text{flow}}$, ${\sigma }_{\text{back}}$, and ${\sigma }_{\text{eff}}$ during tensile testing. (c) Proportion of the ${\sigma }_{\text{eff}}$ in total ${\sigma }_{\text{flow}}$ (${\sigma }_{\text{eff}}/{\sigma }_{\text{flow}}$) at varying strain levels. (d–d’) (g–g’) IPF and TF images near the tensile fracture, respectively. (e–e’) (h–h’) GNDs and BC images of the blue box regions in (d) and (g), respectively. (f) (i) SEM images of the blue box regions in (e) and (h), respectively. (j–l) Dislocation evolution near the fracture under different strains.

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Data availability statement

All relevant data are within the manuscript and its Additional files.