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|Title:||Assessment of the influence of Al-2Nb-2B master alloy on the grain refinement and properties of LM6 (A413) alloy|
Hari Babu, N
|Keywords:||Al alloys;Grain refinement;Heterogeneous nucleation;Solidification;Nb-B inoculation|
|Citation:||Materials Science & Engineering A, 628: pp.230 - 237, (2015)|
|Abstract:||Cast aluminium alloys are important structural materials but their performances are not optimised due to the lack of appropriate grain refiners. In this study the effect of the addition of a novel Nb-based grain refiner on the microstructural features and mechanical behaviour of the LM6 alloy (A413) is studied. Specifically, the effect of Nb-B inoculation is assessed over a great range of cooling rates (2-100 ºC/s). It is found that Nb-based compounds (i.e. NbB2 and Al3Nb) are potent heterogeneous nucleation sites for aluminium and this leads to a significant refinement of the microstructural features. The refinement is not hindered by the formation of silicides, as it happens when using Al-Ti-B master alloys, because niobium silicides form at much higher temperature. It is concluded that the Al-2Nb-2B master alloy is a very effective refiner especially at slow cooling rate and the refinement of the grain size leads to improved performances (homogeneous fine grain structure, mechanical properties and porosity).|
|Appears in Collections:||Brunel Centre for Advanced Solidification Technology (BCAST)|
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