• • Particle size critically governs ignition and combustion via a thermal-mass coupling competition: small particles (9 μm) exhibit long ignition delay (135 ms) but high combustion intensity (7300.4), while large particles (24 μm) ignite rapidly (18 ms) but with reduced intensity (1721.6), indicating a trade-off between ignition response and energy release.
• • A critical size threshold exists between 13 and 16 μm: ignition delay plummets by 71% (from 51 ms to 15 ms) and combustion intensity drops by 54% (from 6041.8 to 2807.5), signifying a mechanistic shift from surface-diffusion control to micro-explosion dominance.
• • The 13 μm Al-Li-Mg alloy provides the optimal balance for solid propellant formulations: ignition delay of 51 ms (62% shorter than 9 μm), longest combustion duration of 928 ms, and near-peak combustion intensity of 6041.8, ensuring both reliable ignition and efficient energy release.
• • Larger particles (16 and 24 μm) promote Li and Mg surface segregation and temperature gradients, inducing micro-explosions that accelerate ignition but reduce combustion completeness, as evidenced by lower spectral intensities (2807.5 and 1721.6) and shorter stable combustion durations (~920 ms).