Eutectic modification of Al-Si alloys with rare earth metals
Contribuinte(s) |
A Kamio Y Ohmori T Sakamoto |
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Data(s) |
01/01/2004
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Resumo |
The effects of different concentrations of individual additions of rare earth metals (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) on eutectic modification in Al-10mass%Si has been studied by thermal analysis and optical microscopy. According to the twin-plane re-entrant edge (TPRE) and impurity induced twinning mechanism, rare earth metals with atomic radii of about 1.65 times larger than that of silicon, are possible candidates for eutectic modification. All of the rare earth elements caused a depression of the eutectic growth temperature, but only Eu modified the eutectic silicon to a fibrous morphology. At best, the remaining elements resulted in only a small degree of refinement of the plate-like silicon. The samples were also quenched during the eutectic arrest to examine the eutectic solidification modes. Many of the rare-earth additions significantly altered the eutectic solidification mode from that of the unmodified alloy. It is concluded that the impurity induced twinning model of modification, based on atomic radius alone, is inadequate and other mechanisms are essential for the modification process. Furthermore, modification and the eutectic nucleation and growth modes are controlled independently of each other. |
Identificador | |
Idioma(s) |
eng |
Publicador |
Japan Institute of Metals |
Palavras-Chave | #Metallurgy & Metallurgical Engineering #Eutectic #Aluminium-silicon Alloy #Solidification #Modification #Rare Earth #Modified Al-7wt-percent-si Alloy #Solidification Mode #Growth #Materials Science, Multidisciplinary #C1 #291302 Physical Metallurgy #671004 Castings |
Tipo |
Journal Article |