Please use this identifier to cite or link to this item:
|Title:||Unidirectional solidification of Zn-Rich Zn-Cu peritectic alloys - II. Microstructural length scales||Authors:||Ma, D.
|Issue Date:||11-May-2000||Citation:||Ma, D., Li, Y., Ng, S.C., Jones, H. (2000-05-11). Unidirectional solidification of Zn-Rich Zn-Cu peritectic alloys - II. Microstructural length scales. Acta Materialia 48 (8) : 1741-1751. ScholarBank@NUS Repository. https://doi.org/10.1016/S1359-6454(00)00003-3||Abstract:||Experimental results are presented of solidification microstructure length scales including η-phase cell spacing, primary ε secondary dendrite arm spacing, size of nonaligned dendrite of primary ε, and volume fraction of primary ε, as functions of alloy concentration (containing up to 7.37 wt% Cu) and growth velocity (ranging from 0.02 to 4.82 mm/s) in the unidirectional solidification of Zn-rich Zn-Cu peritectic alloys. Intercellular spacing (λ) of two-phase cellular structure decreases with increasing growth velocity (V) such that λV 1/2 is constant at a fixed alloy concentration in parametric agreement with the KGT and Hunt-Lu models. The value of λV 1/2 varies from 216 ± 10 to 316 ± 55 μm3/2/s 1/2 with decrease in alloy concentration from 4.94 to 2.17 wt% Cu. These values are much greater than for normal eutectic systems but comparable with monotectic alloys. Dendritic secondary arm spacing (λ2) of primary ε decreases with increasing V such that λ2V1/3 is constant ranging 14.9 ± 0.9 to 75.6 ± 8.1 μm4/3/s1/3 with increase in alloy concentration (C0) from 2.17 to 7.37 wt% Cu, which is in parametric agreement with predictions of arm-coarsening theory. The volume fraction (fε) of primary ε increases with increasing V for Zn-rich Zn-3.37, 4.94 and 7.37 wt% Cu hyperperitectic alloys. Predictions of the Scheil and Sarreal-Abbaschian models show good agreement with the observed fε for Zn-4.94 wt% Cu at moderate V from 0.19 to 2.64 mm/s, but fail at low V of less than 0.16 mm/s and at high V of greater than 3.54 mm/s. The measured average size, Λ, of nonaligned dendrites of primary ε decreases with increasing V such that ΛV 1/2 is constant for a given alloy, increasing from (0.98 ± 0.04) × 103 to (7.2 ± 0.7) × 103 μm3/2/s 1/2 with increase in alloy concentration from 2.17 to 4.94 wt% Cu.||Source Title:||Acta Materialia||URI:||http://scholarbank.nus.edu.sg/handle/10635/98517||ISSN:||13596454||DOI:||10.1016/S1359-6454(00)00003-3|
|Appears in Collections:||Staff Publications|
Show full item record
Files in This Item:
There are no files associated with this item.
checked on Jan 14, 2022
WEB OF SCIENCETM
checked on Jan 14, 2022
checked on Jan 20, 2022
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.