A calorimetric evaluation of the role of impurities in the nucleation of secondary phases in 1xxx Al alloys
- Univ. of Oxford (United Kingdom)
- Alcan International Limited, Banbury (United Kingdom). Banbury Lab.
Superpurity (>99.995 wt% pure) 1xxx series Al-0.3 wt% Fe-0.1 wt% Si alloys with different impurity additions have been melt spun to produce ribbons with microstructures of fine scale {minus}0.1--0.2 {micro}m diameter secondary phase particles entrained in a higher melting point Al matrix. The melting and resolidification behavior at 2K min{sup {minus}1} of the secondary phase particles while entrained in the solid matrix was monitored using differential scanning calorimetry, to simulate the nucleation of secondary phases in liquid interdendritic regions during the final stages of solidification in casting. The melting and resolidification behavior of 500 ppm V and Zr doped superpurity ribbons is the same as that of a commercial purity ribbon. This indicates that V is responsible for the promotion of the metastable FeAl{sub m} phase in the commercial purity ribbon. The presence of FeAl{sub m} in direct chill (DC) cast commercial purity alloys indicates that V also influences phase selection in the faster cooled ({approximately}5--10 Ks{sup {minus}1}) regions of these alloys.
- OSTI ID:
- 323432
- Report Number(s):
- CONF-971201--
- Country of Publication:
- United States
- Language:
- English
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