Synergistic mechanisms of temperature and strain rate on plastic deformation in SLM 3D printed SS316L utilizing hot processing map analysis

The plastic deformation behavior of selective laser melting (SLM) 3D printed SS316L steel has been analyzed at the temperature range 25- 1000℃ (25 (room temperature), 200, 400, 600, 800 and 1000℃) and strain rate range 10^-3-10³s^-1 (10^-3, 10^-2, 10^-1, 10⁰, 10¹, 10² and 10³ s^-1) under compressive loading environments. The flow stress vs. plastic strain results revealed that the flow stress was reduced 136.64% from room temperature to 1000℃ at 10^-3s^-1. Further, the flow stress was decreased 102.86% from room temperature to 1000℃ at 10³s^-1. The flow stress was increased 46.63% from 10^-3s^-1 to 10³s^-1 at room temperature. Moreover, the flow stress was increased 95.07% from 10^-3s^-1 to 10³s^-1 at 1000℃. The temperature and strain rate effect on strain rate sensitivity (m) has been observed for SLM 3D printed SS316L steel. Based on strain rate sensitivity (m), the power dissipation efficiency ([Formula: see text]) and instability dimensionless parameter ([Formula: see text]) map plot contours have been investigated under various hot working parameters for SLM 3D printed SS316L steel. Further, hot working processing maps have been generated by superimposing instability dimensionless parameters ([Formula: see text]) map on the power dissipation efficiency ([Formula: see text]) map for SLM 3D printed SS316L steel. The processing map was further related with investigated material microstructure to identify the hot processing safe and unsafe zone for SLM 3D printed SS316L. The unsafe instability region occurred at the low strain rate range (10^-2 - 10^-1 s^-1), high strain rate range (10²-10³ s^-1) and temperature range (200-400℃, and 800 - 100℃) for 0.02, 0.04, 0.06, 0.08 and 0.10 strain. Further, the remaining area was useful for hot workability. The Vicker's hardness revealed that the hardness was decreased with 3.87%, 12.55%, 22.01%, 32.35%, and 43.70% at 200⁰C, 400⁰C, 600⁰C, 800⁰C and 1000⁰C respectively with respect to room temperature hardness.