In-situ observation of coupled peritectic growth in a binary organic model alloy
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In: Acta Materialia, Vol. 126.2017, No. March, 01.03.2017, p. 329-335.
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TY - JOUR
T1 - In-situ observation of coupled peritectic growth in a binary organic model alloy
AU - Ludwig, Andreas
AU - Mogeritsch, Johann
AU - Pfeifer, Tanja
PY - 2017/3/1
Y1 - 2017/3/1
N2 - Peritectic alloys form a variety of solidification morphologies of which peritectic coupled growth (PCG) is the most peculiar. Because the conditions that lead to PCG are still under discussion, in-situ investigations of the evolution from lateral bands to PCG were carried out by using binary organic TRIS-NPG model alloys at concentrations in the peritectic region. The experiments were done vertically with relatively large rectangle glass tubings. For a hyper-peritectic alloy at growth rates below the morphological stability limits of both solid phases, we found that first the properitectic phase grew while lateral bands of the peritectic phase formed between the glass walls and the properitectic phase. Then, the peritectic phase dominated the growth until lateral bands of the now properitectic phase occurred, again close to the glass walls. Now both phases grew side-by-side as two layers at different depths in the sample. However, the properitectic phase spread locally onto the peritectic/liquid interface, so that patches of peritectic phase surrounded by a properitectic matrix developed. This resulted in creating an unstable PCG mode with cycles of increasing and decreasing phase amounts, which from a side-on view resemble tulip- and onion-like structures respectively.
AB - Peritectic alloys form a variety of solidification morphologies of which peritectic coupled growth (PCG) is the most peculiar. Because the conditions that lead to PCG are still under discussion, in-situ investigations of the evolution from lateral bands to PCG were carried out by using binary organic TRIS-NPG model alloys at concentrations in the peritectic region. The experiments were done vertically with relatively large rectangle glass tubings. For a hyper-peritectic alloy at growth rates below the morphological stability limits of both solid phases, we found that first the properitectic phase grew while lateral bands of the peritectic phase formed between the glass walls and the properitectic phase. Then, the peritectic phase dominated the growth until lateral bands of the now properitectic phase occurred, again close to the glass walls. Now both phases grew side-by-side as two layers at different depths in the sample. However, the properitectic phase spread locally onto the peritectic/liquid interface, so that patches of peritectic phase surrounded by a properitectic matrix developed. This resulted in creating an unstable PCG mode with cycles of increasing and decreasing phase amounts, which from a side-on view resemble tulip- and onion-like structures respectively.
KW - Directional solidification
KW - Morphological stability
KW - Nucleation and growth
KW - Peritectic solidification
UR - http://www.scopus.com/inward/record.url?scp=85008937447&partnerID=8YFLogxK
U2 - 10.1016/j.actamat.2016.12.064
DO - 10.1016/j.actamat.2016.12.064
M3 - Article
AN - SCOPUS:85008937447
VL - 126.2017
SP - 329
EP - 335
JO - Acta Materialia
JF - Acta Materialia
SN - 1359-6454
IS - March
ER -