Understanding Residual Stress and Microhardness Variations in LPBF Fabricated Ti-6Al-4V: Thermo-Mechanical Simulation and Experimental Insights Post Heat Treatment

• Published in: International journal of precision engineering and manufacturing-green technology pp. 1309 - 1319
• Format: Journal Article
• Language: English
• Published: 한국정밀공학회 01.07.2025
• Subjects: 기계공학
• ISSN: 2288-6206; 2198-0810
• DOI: 10.1007/s40684-024-00670-4

The study investigates the impact of heat treatments on residual stresses and mechanical properties in Ti-6Al-4V samples fabricated via laser powder bed fusion (LPBF). LPBF involves complex physical phenomena, including laser-matter interaction and solidification kinetics, which can induce residual stresses and distortions in fabricated parts. To address this, a thermo-mechanical simulation approach was adopted to model the effects of heat treatments on residual stresses. Experimental measurements were then conducted to validate the simulation results, focusing on residual stresses along the build direction. Two temperatures, 670 °C and 950 °C, were selected to reduce tensile stresses and improve hardness, respectively. Simulation results indicated a drop in residual stress from 893.50 MPa in as-printed samples to 205.95 MPa and 276.29 MPa after treatments at 670 °C and 950 °C, respectively. Experimental results showed residual stresses of 930.34 MPa (untreated), 228.45 MPa (670 °C), and 302.21 MPa (950 °C). Moreover, phase analysis identified the β phase in the 670 °C-treated samples, with a reduction in peak intensity noted for both treated samples. Also, microhardness measurements revealed enhancements in the 950 °C treated sample compared to untreated and 670 °C treated samples. Overall, the study provides valuable insights into optimizing heat treatment strategies to enhance the performance of LPBF-fabricated Ti-6Al-4V components. KCI Citation Count: 0