Abstract

RAMIREZ-LEDESMA, A.L.; LOPEZ, H.; HERRERA, R.  and  JUAREZ-ISLAS, J.A.. Caracterización microestructural de una aleacion Co-20% Cr solidificada en molde metalico. Rev. mex. fis. [online]. 2018, vol.64, n.2, pp.122-126. ISSN 0035-001X.  https://doi.org/10.31349/revmexfis.64.121.

It was performed a microstructural characterization of a Co-20 wt. % Cr alloy solidified in a copper metal mold with a cooling rate of 450 K/s, which was selected from a group of Co-20 to 44 wt. % Cr alloys, systematically solidified at different cooling rates (130, 230 and 450 K/s), previously reported [1], with the purpose of reporting the resulting microstructure, which consisted of columnar dendrites without the presence of eutectic phase or intermetallic compounds in interdendritic regions. A cooling rate of 450 K/s was enough to obtain columnar dendrites which were composed of more than 90 % of martensite HCP ε-Co, the remainder being the metastable phase FCC γ-Co. It was identified that a cooling rate between 130 and 450 K/s generates defects such as vacancies, dislocations and stacking faults. The latter served as nucleation sites for the growth of martensite HCP γ-Co plates.

Keywords : Cobalt base alloys; microstructure; solidification; martensite.

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