Metallurgical Reactions and Their Relationships to Enhanced Mechanical Strength in Zr-Bearing YBCO Composite Superconductors

Autor:	Yousuke Yanagi, Shin ichi Takashima, Uichiro Mizutani, Hidehiko Tanaka, Tetsuo Oka, Yoshitaka Itoh
Rok vydání:	1992
Předmět:	Zirconium Materials science Composite number Metallurgy General Engineering General Physics and Astronomy chemistry.chemical_element Microstructure chemistry Flexural strength Phase (matter) Melting point Grain boundary Thermal analysis
Zdroj:	Japanese Journal of Applied Physics. 31:1760
ISSN:	1347-4065 0021-4922
DOI:	10.1143/jjap.31.1760
Popis:	The metallurgical reactions occurring during partial melting of the Zr-bearing YBCO composite superconductors have been investigated in detail by analyzing the DTA, XRD spectra and SEM micrographs of samples subjected to various heat treatments. It is shown that Zr reacts preferentially with Ba to form BaZrO3. As a result, the 123-phase is partially disintegrated and yields CuO and the 211-phase as by-products. The CuO phase in contact with the 123-phase lowers the melting point of the 123-phase to 970°C. The Zr-bearing YBCO sample annealed above 970°C melts partially and contributes to the reduction of voids. In addition, fine BaZrO3 particles precipitated along the grain boundaries form complicated three-dimensional networks. This skeletonlike structure prevents the sample from collapsing during partial melting and reinforces the mechanical strength of composites.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::e959a5e3efc26840baf45bf6330def37 https://doi.org/10.1143/jjap.31.1760 Zobrazit plný text záznamu