Heat Treatment of A20X Alloy Manufactured Using Laser Powder Bed Fusion

The A20X alloy, a metal matrix composite (MMC) designed for laser powder bed fusion (LPBF), requires precipitation hardening treatment to achieve optimal mechanical properties. This study investigates the effect of temperature and duration of heat treatment on the microstructure and mechanical properties of LPBF A20X. The effects of heat treatment temperature and duration on the as-printed material were evaluated using mechanical testing and microscopic characterization. In total, three different regimes reflecting the alloy's response to heat treatment were observed. For low-temperature (180-370 degrees C) heat treatments, material softening (up to 26%) proportional to temperature and duration of treatment was evident. Samples treated at medium temperatures (430-480 degrees C) showed hardening (from 90 up to 115 HV) with increasing temperature and remained unchanged with dwell time. This is attributed to the dissolution of precipitate-formers (Cu/Mg/Ag) promoting solid solution strengthening. At high temperatures (similar to 500 degrees C), the alloy entered the super-saturation regime causing relatively constant hardness (similar to 117 HV).