Abstract
This research investigates the behavior of A205 aluminum alloy, produced through Laser Powder Bed Fusion (LPBF), under hot compression testing using a Gleeble 563 system. Tests were conducted at temperatures ranging from 200 °C to 350 °C and strain rates of 0.01 s⁻¹ to 1 s⁻¹ on both as-built and heat-treated A205 samples. The observed peak stress in true stress–true strain curves suggests dynamic flow softening. Moreover, as expected, a decline in peak stress levels was noted with increasing deformation temperatures and decreasing strain rates. To further understand the stress/strain behavior, Electron Backscatter Diffraction (EBSD) and Transmission Electron Microscopy (TEM) were employed to analyze and track the microstructural changes. Differences in flow behavior, such as increased flow stress and the absence of a yield point in heat-treated samples, are attributable to microstructural changes resulting from heat treatment. Specifically, grain coarsening, observed in both sample conditions, is primarily due to grain rotation-induced coalescence in as-built samples. Dynamic recrystallization (DRX), evident in both deformed as-built and heat-treated samples, was accompanied by dynamic recovery (DRV) as the predominant softening mechanism in as-built samples, in contrast to heat-treated ones. Back stress hardening, resulting from precipitation, was the main hardening mechanism in the heat-treated samples.