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Quantitative Evaluation of Tool Wear in Cold Stamping of Ultra-High-Strength Steel Sheets
Ishat Raihan Jamil,Ali Muhit Mustaquim,Mahmudul Islam,Md Shajedul Hoque Thakur,Mohammad Nasim Hasan 대한금속ᆞ재료학회 2023 METALS AND MATERIALS International Vol.29 No.2
In our study, molecular dynamics (MD) simulations of laser powder bed fusion (LPBF) have been conducted on equimolarFeNiCr medium entropy alloy (MEA) powders. With the development of newer LPBF technologies capable of printing at themicroscale, an even deeper understanding of the underlying atomistic effects of the process parameters on the microstructuraland mechanical properties of the manufactured FeNiCr MEA products is required. In accordance with previous literature,the parameters of the LPBF process have been systematically varied, including layer resolution from 1 to 6, laser powerfrom 100 μW to 220 μW, bed temperature from 300 to 600 K, and laser scan speed from 0.5 Å/ps to 0.0625 Å/ps. Consistentwith prior macroscopic experimental findings, the atomistic results suggest that additive manufacturing using thinner layersimparts higher ultimate tensile strength (UTS) than fabricating with thicker layers. The latter, however, requires a shorterprocess time but induces keyhole defect formation if the laser-induced temperature is not sufficiently high enough. Increasingthe temperature proves useful in mitigating this problem. Enhancement of UTS for the multi-rowed powders has beenobserved by raising the substrate temperature to 600 K, slowing down the laser or by raising the power to 160 μW duringproduction. Beyond certain critical power, however, the UTS of the product diminishes due to the emergence of multiplevacancies. These results will help researchers to find a good balance between the production speed and strength of additivemanufactured products at the nanoscale.
Ishat Raihan Jamil,Ali Muhit Mustaquim,Mahmudul Islam,Md Shajedul Hoque Thakur,Mohammad Nasim Hasan 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.3
In our study, molecular dynamics (MD) simulations of laser powder bed fusion (LPBF) have been conducted on equimolarFeNiCr medium entropy alloy (MEA) powders. With the development of newer LPBF technologies capable of printing at themicroscale, an even deeper understanding of the underlying atomistic effects of the process parameters on the microstructuraland mechanical properties of the manufactured FeNiCr MEA products is required. In accordance with previous literature,the parameters of the LPBF process have been systematically varied, including layer resolution from 1 to 6, laser powerfrom 100 μW to 220 μW, bed temperature from 300 to 600 K, and laser scan speed from 0.5 Å/ps to 0.0625 Å/ps. Consistentwith prior macroscopic experimental findings, the atomistic results suggest that additive manufacturing using thinner layersimparts higher ultimate tensile strength (UTS) than fabricating with thicker layers. The latter, however, requires a shorterprocess time but induces keyhole defect formation if the laser-induced temperature is not sufficiently high enough. Increasingthe temperature proves useful in mitigating this problem. Enhancement of UTS for the multi-rowed powders has beenobserved by raising the substrate temperature to 600 K, slowing down the laser or by raising the power to 160 μW duringproduction. Beyond certain critical power, however, the UTS of the product diminishes due to the emergence of multiplevacancies. These results will help researchers to find a good balance between the production speed and strength of additivemanufactured products at the nanoscale.