Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30013, Taiwan.
Department of Physics, College of Education, Can Tho University, Can Tho City, 900000, Vietnam.
Sci Rep. 2021 May 5;11(1):9610. doi: 10.1038/s41598-021-89022-9.
We demonstrated the design of pre-additive manufacturing microalloying elements in tuning the microstructure of iron (Fe)-based alloys for their tunable mechanical properties. We tailored the microalloying stoichiometry of the feedstock to control the grain sizes of the metallic alloy systems. Two specific microalloying stoichiometries were reported, namely biodegradable iron powder with 99.5% purity (BDFe) and that with 98.5% (BDFe-Mo). Compared with the BDFe, the BDFe-Mo powder was found to have lower coefficient of thermal expansion (CTE) value and better oxidation resistance during consecutive heating and cooling cycles. The selective laser melting (SLM)-built BDFe-Mo exhibited high ultimate tensile strength (UTS) of 1200 MPa and fair elongation of 13.5%, while the SLM-built BDFe alloy revealed a much lower UTS of 495 MPa and a relatively better elongation of 17.5%, indicating the strength enhancement compared with the other biodegradable systems. Such an enhanced mechanical behavior in the BDFe-Mo was assigned to the dominant mechanism of ferrite grain refinement coupled with precipitate strengthening. Our findings suggest the tunability of outstanding strength-ductility combination by tailoring the pre-additive manufacturing microalloying elements with their proper concentrations.
我们展示了预增材制造微合金元素的设计，用于调整铁基合金的微观结构，以实现其可调的机械性能。我们通过调整原料的微合金化化学计量比来控制金属合金体系的晶粒尺寸。报告了两种特定的微合金化化学计量比，即纯度为 99.5%的可生物降解铁粉（BDFe）和纯度为 98.5%的可生物降解铁粉-钼（BDFe-Mo）。与 BDFe 相比，BDFe-Mo 粉末具有较低的热膨胀系数（CTE）值和更好的抗氧化性能，在连续的加热和冷却循环中。选择性激光熔化（SLM）制造的 BDFe-Mo 表现出 1200 MPa 的高极限拉伸强度（UTS）和 13.5%的良好伸长率，而 SLM 制造的 BDFe 合金则表现出低得多的 UTS 为 495 MPa 和相对较好的伸长率为 17.5%，表明与其他可生物降解系统相比具有强度增强。BDFe-Mo 中这种增强的机械性能归因于铁素体晶粒细化与析出强化的主导机制。我们的研究结果表明，通过调整预增材制造微合金元素及其适当的浓度，可以实现优异的强度-延性组合的可调性。
