Dispersion of ceramic nano-particles in the Al-Cu alloy matrix using two-step ultrasonic casting and resultant strengthening
Dispersion of ceramic nano-particles in the Al-Cu alloy matrix using two-step ultrasonic casting and resultant strengthening
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DOI：
10.1016/j.msea.2017.09.117
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发表时间：
2017-12
期刊：
影响因子：
6.4
通讯作者：
H. Vishwanatha;Jayakumar Eravelly;C. S. Kumar;Sudipto Ghosh
中科院分区：
文献类型：
--
作者：
H. Vishwanatha;Jayakumar Eravelly;C. S. Kumar;Sudipto Ghosh
采用两步超声铸造法制备了纳米Al 2 O3颗粒在Al-3Cu基体中的分散体，并对制备的纳米复合材料进行了表征。作为结果的Al 2 O3分散的两个步骤的过程中，显着的晶粒细化，晶粒形态的变化，并在形态的CuAl 2相的变化进行了观察。纳米颗粒的分散是均匀的，在一个相当大的部分晶粒。然而，在剩余的晶粒中，观察到富Al相和CuAl 2的边界附近的偏析，这表明从两端推动。晶粒尺寸的减小和CuAl 2形貌的改变归因于Al 2 O3纳米弥散相的存在提高了异质形核速率。该分布解释的基础上解团聚由于空化和Cu的影响-（a）的润湿性的Al-Cu与Al 2 O3，和（B）的纳米粒子的凝固前沿的推动。强化后的分散阐明了一个攀登机制，这已经提出了较早的文献。延展性的增加归因于作为纳米复合材料中的两步超声处理的结果的较低程度的不均匀性，与基础合金相比。
The work describes the dispersion of the Al2O3nano-particles in the Al-3Cu matrix using a novel two-step ultrasonic casting technique and characterization of the bulk nanocomposite. As a result of Al2O3dispersion by the two-step process, significant grain refinement, change in the grain morphology, and change in the morphology of the CuAl2phase were observed. The dispersion of nano-particles was uniform in a substantial fraction of grains. However, in the remaining grains, segregation near the boundary of Al-rich phase and CuAl2was observed suggesting pushing from both the ends. The reduction in grain size and change in the morphology of CuAl2were ascribed to the increased heterogenous nucleation rate due to the presence of Al2O3nano-dispersoids. The distribution was explained on the basis of deagglomeration due to the cavitation and influence of Cu on— (a) the wettability of the Al-Cu with Al2O3, and (b) pushing of nano-particles by the solidification front. The strengthening upon the dispersion was elucidated in terms of a climbing mechanism, which has been proposed earlier in the literature. The increase in the ductility was attributed to the lower extent of the inhomogeneity as a result of two-step ultrasonication in the nanocomposite as compared to the base alloy.