Ramakrishnan Bhupendera Prashanth, Lei Qian, Misra Amit, Mazumder Jyoti
Department of Mechanical Engineering, College of Engineering, University of Michigan, Ann Arbor, 48109-2136, USA.
Department of Materials Science and Engineering, College of Engineering, University of Michigan, Ann Arbor, 48109-2136, USA.
Sci Rep. 2017 Oct 18;7(1):13468. doi: 10.1038/s41598-017-13953-5.
Bimodal ultrafine eutectic composites (BUECs) exhibit a good combination of strength and plasticity owing to a dual-hierarchy in eutectic length-scales in the microstructure. The present study investigates the variation of phase, morphology, feature length-scales and modality of microstructures obtained in a AlCuSi (at. %) ternary alloy after laser surface remelting. A novel approach of varying component bimodal eutectic volume fractions by controlling the cooling rate of the laser solidification process has been presented. The volume fraction of the fine eutectic matrix has a profound effect on the flow strength. Laser remelted microstructures with volume fractions of the fine eutectic varying from 25 to 40% exhibiting compressive flow strengths ranging from 500 to 900 MPa have been obtained. The volume fraction of the fine eutectic decreased with cooling rate and completely ceased to exist at cooling rates greater than [Formula: see text].
双峰超细共晶复合材料（BUECs）由于其微观结构中共晶长度尺度的双重层次结构，展现出强度和塑性的良好结合。本研究调查了AlCuSi（原子百分比）三元合金在激光表面重熔后所获得的微观结构的相、形态、特征长度尺度和模态的变化。提出了一种通过控制激光凝固过程的冷却速率来改变组分双峰共晶体积分数的新方法。细共晶基体的体积分数对流动强度有深远影响。已获得细共晶体积分数在25%至40%之间变化、压缩流动强度在500至900MPa之间的激光重熔微观结构。细共晶的体积分数随冷却速率降低，并且在冷却速率大于[公式：见原文]时完全不再存在。
