Hybrid Materials Center (HMC), Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 209 Neugdong-ro, Gwangjin-gu, Seoul 143-747, Republic of Korea.
High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seoungbuk-gu, Seoul 136-791, Republic of Korea.
Sci Rep. 2017 Jan 9;7:39959. doi: 10.1038/srep39959.
In the present study, the microstructural evolution and the modulation of the mechanical properties have been investigated for a Co-Cr-Mo (CCM) ternary eutectic alloy by addition of a small amount of copper (0.5 and 1 at.%). The microstructural observations reveal a distinct dissimilarity in the eutectic structure such as a broken lamellar structure and a well-aligned lamellar structure and an increasing volume fraction of Co lamellae as increasing amount of copper addition. This microstructural evolution leads to improved plasticity from 1% to 10% without the typical tradeoff between the overall strength and compressive plasticity. Moreover, investigation of the fractured samples indicates that the CCMCu alloy exhibits higher plastic deformability and combinatorial mechanisms for improved plastic behavior. The improved plasticity of CCMCu alloys originates from several deformation mechanisms; i) slip, ii) deformation twinning, iii) strain-induced transformation and iv) shear banding. These results reveal that the mechanical properties of eutectic alloys in the Co-Cr-Mo system can be ameliorated by micro-alloying such as Cu addition.
在本研究中，通过添加少量铜（0.5 和 1 原子%），研究了 Co-Cr-Mo（CCM）三元共晶合金的微观结构演变和力学性能的调节。微观结构观察表明，共晶组织存在明显差异，如层状结构的断裂和层状结构的良好排列，以及随着铜添加量的增加，Co 层的体积分数增加。这种微观结构演变导致塑性从 1%提高到 10%，而整体强度和压缩塑性之间没有典型的折衷。此外，对断裂样品的研究表明，CCMCu 合金表现出更高的塑性变形能力和组合机制，以改善塑性行为。CCMCu 合金的塑性提高源于几种变形机制；i）滑移，ii）变形孪晶，iii）应变诱导相变和 iv）剪切带。这些结果表明，通过微合金化如添加 Cu 可以改善 Co-Cr-Mo 系共晶合金的力学性能。
