Phase Selection in Solidi?cation of Undercooled Co–B Alloys
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2017年第4期
论文作者：X.X.Wei W.Xu J.L.Kang M.Ferry J.F.Li
文章页码：352 - 358
摘 要：A series Co-（18.5–20.7） at.% B melts encompassing the eutectic composition（Co81.5B18.5） were solidi?ed at different degrees of undercooling. It is found that the metastable Co23B6 phase solidi?es as a substitute for the stable Co3 B phase in the alloy melts undercooled above a critical undercooling value of 60 K.The Co23B6 and α-Co phases make up a metastable eutectic. The corresponding eutectic composition and temperature are Co80.4B19.6 and 1343 K, respectively. On exposure of the metastable Co23B6 phase at a given temperature above 1208 K, it does not decompose even after several hours. But it transforms by a eutectoid reaction to α-Co + Co3 B at lower temperature.
X.X.Wei1，W.Xu2，J.L.Kang1，M.Ferry2，J.F.Li1
1. State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University2. Australian Research Council Centre of Excellence for Design in Light Metals, School of Materials Science and Engineering, The University of New South Wales
摘 要：A series Co-（18.5–20.7） at.% B melts encompassing the eutectic composition（Co81.5B18.5） were solidi?ed at different degrees of undercooling. It is found that the metastable Co23B6 phase solidi?es as a substitute for the stable Co3 B phase in the alloy melts undercooled above a critical undercooling value of 60 K.The Co23B6 and α-Co phases make up a metastable eutectic. The corresponding eutectic composition and temperature are Co80.4B19.6 and 1343 K, respectively. On exposure of the metastable Co23B6 phase at a given temperature above 1208 K, it does not decompose even after several hours. But it transforms by a eutectoid reaction to α-Co + Co3 B at lower temperature.
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